Completely confused and stuck? What you need to realize is that in 5D chess, pieces can move and capture through time and timelines. For example, a Rook can move any clear distance in any dimension - north, south, east, west but also into the past or into adjacent timelines. Checking a King in the past is an especially powerful move, since the King in the past can't simply move out of the way.

If you don't get it at all, watch this excellent tutorial video: https://www.youtube.com/playlist?list=PLDlKBW97umdtjmUvg1M56PQHWL_qEisfZ Or read this excellent tutorial guide: https://cs2bus.com/sharedfiles/filedetails/?id=2176513845 And it will help you visualize 5D chess piece movement.

Anyway, on with the puzzles! The first one's a doozy, but it gets easier after that!

Rook Tactics I: At first it seems like there's no useful moves you can make - if you check the King in the present with your Rook, it just walks out of the way. Moving your King into the present or past seems to do nothing exciting (you've only got one turn and it never puts the king in check, so it's a non-starter). What if we think five dimensionally? We can try moving the rook into the past - but the king on the new timeline just moves out of check. - What we need to realize is - the Rook can't just MOVE into the past. It can also CAPTURE into the past. Can we use this to our advantage? Can we do a kind of check that is impossible in 2D chess? - Just move your rook to the northeast corner. It checks the king in the past. (The AI can't branch to get away from it since it would advance the checked timeline and allow me to make my checkmating move, and it has no other timelines it can branch to recede the Past while choosing to not play in the checking timeline.)

Rook Tactics II: This would be checkmate in typical chess. But thanks to time travel, our opponent has a trick up their sleeve. Do the standard (as in Chess) mate. Enemy king will branch to remove their present king from check (they can do it since it's not threatened in the past in that timeline, so it removes the check condition). - Then do the same move again in the new branch. Too bad they couldn't run further!

Rook Tactics III: In the last puzzle we saw travel into the past. But there is one more dimension that pieces can move and attack along. Move a rook fully north to check a king across timelines. (The AI can't do anything here except move its pawn - it again has no other timelines available to branch to recede The Present. We weren't obliged to play on the future timeline, and in fact if we do the AI can get out of it by sending their king into the past to capture our rook. So we have to make a move and NOT make another move.)

Rook Tactics IV: Some things we can try that don't work: The black rooks can make moves into the past and across timelines, but don't result in check. Also doesn't work: We can move the top board black rook to check a present king, but the present king can just move, so this this leads to nothing good.. So instead, what if we move the top board black rook onto the position a white king used to be in? Then it threatens check by moving into the past to capture the past king. - But the white king in the present can capture the black rook. - Therefore the solution is... To move the bottom board black rook into the same rank and file as the bottom board black rook! Then the top board black rook is protected and can't be captured by a king (it would be captured back by the bottom board black rook). This is checkmate.

Rook Tactics V: This one is tricky! Do the standard Chess mate. Again, enemy king will branch to remove their present king from check. - Now what? We can check the king with the rook in the new branch, but surely it'll just get captured by the king to stop mate, right? Are we meant to do something else instead? - (One last hint: Pieces can be defended from other timelines.) - Nope! Just move the rook to the same position. Well, why does it work? Because they can't branch to remove mate (two kings AND it'd be an inactive timeline and no other timelines to branch instead), and if they capture the rook instead, your rook from a parallel timeline can capture back. Cross-timeline defense! (If you're unconvinced, try making the capture as black and the game will point it out to you.)

As with the Rook, the Knight can also make moves that are partially or fully in time-like dimensions. For example, you could make a move that's 2 into the past and 1 north, or 1 into an adjacent timeline and 2 west.

Knight Tactics I: There's no move here that puts the present king in check... Hint: But if you put a PAST king in check, then you'll win! How can we do this? Solution: Move the knight 2E 1N. The knight now checks the black king 2N and 1 turns in the past, and the opponent has way to capture your knight or make a move elsewhere, so they have lost.

Knight Tactics II: Again, there's no move here that puts the present king in check... Hint: Or even a king from one turn in the past... Hint: But there's TWO turns of past in this puzzle. Can we put a king TWO turns in the past in check? Solution: Yes! Move the knight 2N 1W. It checks the black king 1N and 2 turns in the past.

Knight Tactics III: This one is trickier. We have two knights, a second timeline, and it's not an obvious simple move like either of the previous two puzzles. Ideas that don't work: Just like in regular Chess, simply checking the enemy king in the present does nothing. First we can try moving the upper white knight 2E and one timeline north to check that black king, but the new timeline is inactive (we made more than one more timeline than our opponent) so our opponent isn't forced to play in it, and the king could just move out of the way anyway. No good. (Similarly, any other move that makes a new timeline doesn't work as the opponent can ignore it.) Next, we can try moving the upper knight 2E 1N. It SHOULD work since the next turn we play on this timeline will be to move that knight 2E 1 turn into the past and capture that black king... BUT while Black doesn't HAVE to play on timelines past The Present, he can CHOOSE to do so, and they can use the king from that timeline to capture the knight in this timeline. Darn. Hint: What if instead of threatening check through past, we threaten check through timelines? Solution: When all else is eliminated, the only thing left to try must be the solution - move the upper knight 2N 1E. This puts the white knight 2E, 1 timeline north away from a past black king, black must play on this timeline since it's in the present, black can't move any other piece further in the past to rewind the present, and black can't capture the knight. So, it's checkmate!)

Knight Tactics IV: Hint: Hmm... No movement in the present checks a past king, so we'll have to make a new timeline. Hint: Imagine where the new timeline will appear (it branches off to the south as a new next turn from when your piece landed, with the knight where you put it) and try to calculate that it checks some past king, since it can't checkmate a present king. Solution: Move your knight 1N and 2 turns past. On the new board which Black must play on, it checks a king 2N and 1 timeline north.

Knight Tactics V: A similar situation to Knight Tactics IV. Hint: Once again you're making a new timeline. Hint: You need to make sure your Knight can't be captured in addition to delivering past check. Solution: Move your knight 2W 1 turn into the past. In this new timeline it attacks a past black king 2N 1 timeline north. If you instead moved it 2N 1 turn into the past, it would deliver past check but would also be capturable by the pawn, thus not checkmate. So this is the only move that works, even though both spatially line up.

Knight Tactics VI: At first this looks inscrutable, but if you just do moves that seem intuitively useful, then it will fall into your lap like magic. Check, then check, - then go 2E and 1 turn into the past. In the new branch you are doing a mammoth time only 2 past 1 timeline check of the original king in the past with a defended knight (so it can't be captured). I'm not sure what you'd do if the enemy king moved differently, but it doesn't? Possibly it doesn't matter what the enemy king does? Oh, but it DOES matter what first move your knight makes since it has to protect your knight in its final move. And after that there's only one way to move it into position, which is really funny, haha.

NotAPenguin's alternate solution: Start by moving the king NE. this one is delightfully silly AND deterministic, I think because every other move the king could make on the AI's first turn is an even faster mate, and the AI's second turn is completely irrelevant. https://cdn.discordapp.com/attachments/715057331142000640/736901220584783882/SPOILER_unknown.png

edderiofer's alternate solution: Start by moving 1N2E. There are three different versions, depending on the AI king's final move you have to do a different knight move on the final board: https://cdn.discordapp.com/attachments/715057331142000640/736904147819036692/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736904871936131162/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736905136755965962/SPOILER_unknown.png - Note: This might not be a valid solution...? edderiofer thinks that if the king escapes 1 timeline up (instead of 1 timeline 1 future), then you can't mate anymore. https://media.discordapp.net/attachments/715057331142000640/736906139521908766/SPOILER_unknown.png Further analysis pending.) - He also says: OK, I think this solution works, UNLESS the engine decides to warp the king back in time halfway through, in which case all bets are off. https://cdn.discordapp.com/attachments/715057331142000640/736910410241933312/unknown.png Further analysis pending.

SexyLexi's alternate solution: Start by moving 1N2W. The AI king has MANY different choices (2 on the first turn, 2+ on the second turn) so you have to react to every possible outcome. Examples: https://cdn.discordapp.com/attachments/715057331142000640/736905009371021352/unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736905556333297737/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736906678448029786/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736907329123123261/SPOILER_unknown.png

broney's alternate solution (yes, there are a lot): Start by moving 2N1W. - I haven't analyzed to see if there are alternate lines: https://cdn.discordapp.com/attachments/715057331142000640/738194324101267486/SPOILER_knights6.PNG

Knight Tactics VII: This is similar to Knight Tactics IV and V, but slightly bigger brained. Take your black knight 2 turns 1 timeline into the second branch (advancing it instead of making a new branch). From this point, after your opponent responds, it threatens the past king in the branch with a 2N 1 past leap. It can't be taken, branching doesn't negate the check, and they can't branch elsewhere. Checkmate!

Bishops can move any distance in two dimensions - in Chess this means two space-like dimensions, but in 5D chess you can substitute one or both dimensions for a time-like one to threaten past and other timeline kings.

Bishop Tactics I: Some things that don't work: We can check the black king in the present - but then the black king moves or captures. Or: We can move the white bishop 1 turn in the past and 1 tile north (this threatens check with a 1 turn past, 1 tile north move on the new timeline to capture a black king!) but the black pawn captures the white bishop and it's not mate. - We need to think about the bishop's new power to execute checks in the past. - Aha! What if we move the white bishop 2 north and 2 west? This is checkmate - on our next move we threaten to move 2 past and 2 east and capture a past king, and black has no defense against it.

Bishop Tactics II: Now that we know how bishops can attack past kings, we can put our knowledge to use. If we move the bishop 2 north 2 west, then it threatens check on a past king (by moving 1 past 1 east on its next turn), but the black king can just capture it. - But if we move 1 north 1 west, we get the same check threat, AND it's protected by our white king, so the black king can't capture it. And that's checkmate!

Bishop Tactics III: Wait, where am I meant to move the Bishop this time? ... AM I meant to move the Bishop? - Then, the trick is your bishop is already in position to attack the king in the past - so just protect it with your King and mate happens.

Bishop Tactics IV: Now we need to think in terms of the new dimensions. Things that don't work: We can try moving our bishop adjacent to the black king to threaten a 1 past mate, but the black king just captures back. We can try moving our bishop back in time to where it's 2 tiles orthogonally away from a black king - but it can't actually threaten mate in the past like this, since it'll be on a new timeline! - So maybe instead, We threaten mate from a different timeline? - Specifically, we move the bishop 2 past 2 east. From this new timeline, it threatens a past black king 1 timeline-north 1 north and black can do nothing to stop it.

Bishop Tactics V: We start in check, but it's not hard to deal with. But how do we *deliver* check? Ideas that don't work: Leaving the bottom board black bishop in place doesn't work, since that timeline isn't 'old' enough yet - the bishop can move at most 2 past even after another turn passes. - We can move our top board black bishop 1 timeline-south 1 north. It does deliver check, BUT our king on that board is still in check, so no good. - We can also move our bottom board black bishop 1 timeline-north1 north. Same problem - delivers check but we're in check on the top board still. Observation: Since we need to move our king on the top board, it's unlikely that we can deliver the check from the top board. The solution: Move the bottom board bishop 1 past 1 north. It rewinds the present (so the top board check no longer matters) and threatens check 2 timeline-north 2 north on a past white king - white can't do anything about this. And in fact if we DID move on the top board, we'd miss mate - white's knight could capture our black bishop and prevent it.

In 2D chess, pawns can move forward and capture diagonally forward. In 5D chess, they can also make timeline moves 'forward' (towards your enemy's timelines) and purely timelike captures diagonally forward (one timeline 'forward', and one turn into the past or future).

En passant still works too, but is purely spatial in nature.

You also cannot have a partially spacelike, partially timelike capture, e.g. you cannot capture 1 rank forward one turn into the past, or 1 file to the side one timeline towards your opponent.

Pawn Tactics I: A simple reminder of what kinds of moves pawns are capable of. It's a purely 2D chess puzzle - make the pawn capture. The enemy king cannot dodge the pawn, and capturing the pawn gets the king captured by the knight, and nothing else can capture the pawn back.

Pawn Tactics II: Ideas that don't work: Promoting the bottom board white pawn into a queen (and just moving the white pawn on the top board forward) delivers check, but a black king can just capture the white queen back. So instead we need to: Move the bottom board white pawn one *timeline* forward. This forks the two enemy black kings - either one could escape but the other would still be threatened, AND the pawn is defended and thus can't be captured by a black king, and no other black pieces threaten the white pawn. Never thought you'd say the words 'king fork', did you?

Pawn Tactics III: Ideas that don't work: You can rule out either of the bishops checking the bottom timeline king, since it can just be captured back. - You can also rule out either of the bishops checking the top timeline king, since the parity is always wrong (it would need to be a black coloured bishop to check a white coloured king across one timeline). - So I guess it IS pawn tactics, so maybe the solution is... Moving the white pawn two tiles forward?? YES, because then it checks the black king 1 timeline-north 1 past, which is a valid, purely timelike diagonal capture move a pawn can do. (Also, black can't capture that pawn with the black king since it's defended by a bishop, and no other pieces can capture it, and black can't time travel far enough to forego playing on that board.)

Now we're going to look at some ways in which combinations of pieces can together cause a mate.

Combination Attacks I: This wouldn't be checkmate in regular chess, so probably at some point we threaten past mate.- Check with your rook. King only has one tile to move to. - Then past-check with your knight (2 N 1 past move) and AI can't do anything about it.

Combination Attacks II: We'd love to threaten mate with the knight (2 N 1 past yet again). But the enemy's rook checks our king! Stop and think for a moment - this Rook isn't mating us through the past, but through the Present. - If it has to travel through the Present, then we have more options than if it was a Past king being checked - it's practically like normal chess now! - Ah - if we advance a pawn, it can *block* the intermediate tile the Rook has to travel through. (The Rook has to travel in a straight, unobstructed line to threaten our King!) Then we can submit our moves and get mate. - (Remember that the Knight has to go to the TOP board, not the middle board, or else you cannot also move a pawn on the middle board and block the Rook!)

Combination Attacks III: At first it doesn't look like you can do any kind of mate in the present or past with the rook or king! So you need to realize that the pawns matter - specifically, a pawn can make a 1 past/future 1 timeline capture, and we use this to check a past King. - Specifically, we take the rook back as far as it can go - just having this branch existing (and forcing the opponent to make a play on it) means that either the topleft black pawn can capture the king 1 future/1 timeline. If the king tries to capture it then it just gets captured in the present by a pawn normally.

Combination Attacks IV: A lot of things fail to work here: You can make present checks with the rook or by moving the rook or bishop back in time, but it doesn't seem to go anywhere, the king just walks out of the way and you don't finish in time. You'd love to make a past attack with the rook or bishop, but the problem is that all the tiles you can do it from are next to the king, and it takes too many turns to move a piece into position and defend it at the same time.
Then finally it hits you - the only reason why I can't attack the past king is because the present king defends all the useful tiles, right? - What if I threaten it with my bishop to force it away so my rook can attack the past? And it works! It's a check chase that ends in checkmate. Feels good.

Alternate solution: Just make a meaningless move with your King. - AI King can't stay where it is or move to any other tile protecting the northeast corner, so now you can move your Rook in and checkmate the past King in the exact same way.

Combination Attacks V: Well, this sucks. The puzzle starts with a Knight in the Present threatening check on a King in the Past. Nothing we can do in the present captures that Knight, therefore we cannot play on the top timeline. - Therefore we must branch into the Past on the bottom timeline, then figure out how to mate in one from there. - Let's send the Knight back in time as far as possible and see what we can do after that. - After doing that, one of our Knight moves on the new timeline threatens mate. Can you see which one it is? - It's the one that captures the black Knight in the top timeline! It also threatens checkmate (since it checks a black King in the past) and black can do nothing about it.

Some variations on a classic Chess mate. Probably the easiest puzzle set, but a joy to complete still.

Backrank Basics I: Just showing that a rook can checkmate a king behind pawns. In fact, this also works in regular chess the same way - there's no past or timelines for the king to retreat too.

Backrow Basics II: Showing that it can't be stopped with a blocking piece if the other player doesn't have another timeline or a way to capture the king - now the king CAN escape to the past, but the only tile available is... still in the way of the rook! Dun dun dun! But again, when the pin started, there was no past/other timelines to retreat into.

Backrow Basics III: Finally there IS past to retreat into - so what happens? You just do the same move on the newly branched timeline. Checkmate! So I guess the king really does have to escape into ANOTHER timeline so that history doesn't just repeat itself with two kings instead of one.

Backrank Basics IV: An evolution of the tactic you've been using thus far: It doesn't seem like we can threaten checkmate in the present, so maybe... - You take your rook back into the past when you COULD do the Backrank Basic attack.

Solution A: Go into the past immediately. Enemy king will try to escape to a new timeline. - Don't play in the future - this gives you the tempo to move your rook up into position, then onto the prime timeline again to check both kings. https://cdn.discordapp.com/attachments/715057331142000640/736560336219537469/SPOILER_unknown.png

Solution B: Go for check right away, then go into the past. - When your opponent branches to flee, your already well positioned rook can move between timelines and checkmate. https://cdn.discordapp.com/attachments/715057331142000640/736560435075088464/SPOILER_unknown.png

Queens are EXTREMELY strong in 5D chess. Not only can they move like a Rook or a Bishop, but they can move simultaneously on THREE or even FOUR dimensions. That means that they can move into the past or future or timelines or both at once, while also making a 2D queen move (or not!) on those boards. Practically any hole in your opponent's defense can be exploited by lining up a Queen at the appropriate place in a different board, such that it moves the same number of tiles in all relevant dimensions at once to threaten mate.

Queen Tactics I: Queens are really strong! They can attack on a spatial diagonal AND back in time, so just protect it with your king and it's unstoppable.

Queen Tactics II: There are many different solutions to this puzzle!

The key observation is: So our goal is to check the king in the past - There are five tiles that we can do it from. 2W, 2SW, 2S, 2SE, 2E. If we can get our Queen to any of those tiles without being captured, then we win. Examples: https://cdn.discordapp.com/attachments/715057331142000640/736562694169165824/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736563316444364820/SPOILER_unknown.png

But that's not all: If we can't get to one of those tiles, we can instead branch into the past, moving to one tile of where the king moves to on its turn. We then checkmate the king in the past from the second branch. There are a ridiculous number of possible solutions, for example: https://cdn.discordapp.com/attachments/715057331142000640/736822054371983411/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736823113836265523/SPOILER_unknown.png https://cdn.discordapp.com/attachments/715057331142000640/736823209693020170/SPOILER_unknown.png

In fact: According to Discord user edderiofer, every queen move that doesn't instantly lose the queen is a solution, no matter what the enemy king does. Can you find them all?

Queen Tactics III: Well, we don't have a queen but... We can make one by promoting a pawn! Well, where would we like it to be? It's a mate in three, but a queen is so strong that we can probably check a king in the past from anywhere once we have a queen. But the first two pawns can be captured by the king before we get a turn with them post-promotion, so it has to be the third. Then just leave it in place - it's already in perfect position to mate the pastmost king. Easy.

Queen Tactics IV: This starts off in a funny position - if we make any non-threatening move, the AI's white knight leaps 2 past 1 west and creates a branched timeline where WE'RE checkmated (the knight has a 2 west 1 timeline-down checkmate opportunity on a past king and we have to play in that branch, can't branch deeper into the past and can't capture the knight). This does limit our movement options, therefore - we have to make a move that prevents this response. -
In other words, we have to check the king in the present (so the knight killer move can't be made), in such a way that our queen doesn't immediately get captured. - Then, we can use our queen to mate a past king and there's no response to that. In this case, the correct moves are: Queen 3 SE, king 1 E. Or queen 1 SE, king 1 E. (Queen 1 S doesn't work, since it doesn't threaten past mate in a turn.)

Kings are like a Queen but limited to one move - so they can move one tile in 1, 2, 3 or 4 dimensions at once. This gives them a lot of angles to escape - but also to attack...?

King Tactics I: At first this is like... huh? Since OBVIOUSLY a king can never put a king in check, since the other king puts it in check first! Even if it's across time or timelines. But there is one exception to this - you can check a king in the past and it can't fight back!
So what do we do? Moves in the future or that make new future branches don't seem to help, since our opponent can just choose to not play on them. - We can make a new present branch, but it doesn't seem like we can threaten any exciting lethals. - Instead, we make a present move in the present - simply move the black king one NE. It threatens triple checkmate! Cool!

King Tactics II: It seems like the Present board is full of black king bullies - we can't get anywhere in the top two rows without them threatening some kind of same or cross timeline check, but yet all black kings are up there, so we need to get close, right? But what happens if we go into the past? - What rule determines where a new timeline will branch? - In fact, here's how we do it: Present white king goes to the W square of the original timeline's first turn. From there, it threatens check on a king in the past in the middle timeline, and no black kings are in range to threaten it. If the new timeline was adjacent to the two-black-king timeline, this wouldn't work!

King Tactics III: This seems like nonsense at first - every white king move you can make puts it next to a black king that can retaliate or looks pointless. So what's white to do? Hint 1: Don't forget that the ONLY way a King can check another King is if it is checking a past king AND no present or future king can retaliate. Hint 2: Why is there a black pawn in the top left corner on one board? What move of yours is it trying to prevent? Solution: Move the top board white king 1 north 1 past 1 timeline-south. It forks onto a new timeline. On this new timeline, it checks a black king 1 timeline-north 1 north 1 east. Black can't retaliate because the future black king that COULD do it is too far away in timelines. (In other words, if you tried this move with the BOTTOM board white king, you'd be moving into check.)

Unicorns are a fairty chess piece unique to higher dimensional variants. While rooks move in one dimensional lines and bishops in two dimensional lines, unicorns move in *three* dimensional lines.

You can think of them as having a small fragment of the weird movement powers of the Queen:

* They can move (and therefore threaten capture and check) diagonally backwards in time or sideways through timelines.
* They can move orthogonally if they are also moving diagonally through time and timelines at the same time.

If you want to practice with unicorns outside puzzles, they only exist in some variants, such as:

Focused - Just Unicorns
Misc - Excessive
Misc - Timeline Fragments
Misc - Timeline Strategos

Unicorn Tactics I: Things that don't work: Any of the unicorn moves! All four don't line the unicorn up for a check of any king on any triagonal. Then you realize: The unicorn is already in position to deliver check - 2 north, 2 east, 2 past will check a black king if it just holds in place. Therefore the solution is: Make any move with your king, and black's past king is checked, and black can't do anything about it.

Unicorn Tactics II: Immediate observation: We must either move to the top board from the bottom board or time travel into the past, or else we can't finish our turn. Hint: Given what you know about how unicorns move (and therefore deliver check), what tiles radiating out from a past king can a unicorn deliver check from? The solution: Move the white unicorn 1 north, 1 west, 1 timeline-north. It delivers check to a past black king 2 north, 2 east, 2 past. Consider that a queen could have also done this checkmate!

Like Unicorns, Dragons are another fairy chess piece - this time, they move along all *four* dimensions at once, the last component of movement a queen has. This means they must move the same distance in rank, file, time AND timeline all at once! This makes them a very clunky piece to use - they are moving in diagonals on the board AND in the timelike dimensions or they are not moving at all.

In variants, they can be witnessed in:

Focused - Just Dragons
Misc - Excessive

Dragon Tactics I: Hint: Use the same visualization strategy you did in Unicorn Tactics II - what quadragonal sightlines radiate out from past white kings? And where do they overlap with where a dragon is or could move to? The solution: Move the bottom black dragon 1 timeline-north 1 past 1 north 1 east (it should be adjacent to two white kings and a black dragon. This threatens check on a white king 1 timeline-south 1 past 1 north 1 east. (And it's defended by a black pawn so it can't be captured by a white king.) Whew! What a mouthful. But this is a kind of attack that you need to understand because queens in Standard could have done this, too!!

Mostly because Queens are so strong, there are several kinds of mate traps that occur in standard play that you should categorically try to avoid. Watch out for attacks like these and try to bait your opponent into them!

Opening Traps I: Time to demonstrate the strength of queens in real situations! When our opponent moves a pawn out of their pawn line, it leaves a hole through which a queen can attack backwards through the past - big mistake. - All we have to do is line up to stick a past line through the hole. In this case, we move our queen 3 W (capturing a pawn) and it perfectly lines up to attack the past-most king and can't be taken.

Opening Traps II: Oh no, we lost our queen! Anyways, Hint: The square below the white king has been open for a while - even without a queen, that just screams 'vulnerable'. Solution: Move the black bishop 1 north 1 east. It threatens the white king 3 north 3 past, and white can't do anything about it. Keep your king protected!

Opening Traps III: Hmm, this time there's a knight blocking us in the present. Does that matter? Similar idea, except we fit through the hole diagonally instead of orthogonally. Even though a knight is in the way in the present, it doesn't matter in the past!

Opening Traps IV: This time if we just try to threaten check in the present, our Queen gets captured and it's thoroughly unexciting. Could we do something else useful with the Queen? Maybe in the past? - The trick is to attack the pawn adjacent to the king... in the PAST. By doing this, your queen is defended by your own queen, preventing your opponent from capturing it with the King (which is what they'd do if you attacked in the present). - Their only option is to make a really far back in the past move... - but then you can just attack the king with your queen in this new timeline. Now they have the following situation:
1) They're checked in +1L.
2) They're also checked in -1L, and the only moves that break the check don't travel back in time, so the check in +1L can't be postponed.
(If you do something in +1L besides attack the king, then they can make another time travel move.)

Alternate solution by Discord user kittlish: White bishop b5xc6 (capturing the knight and giving check). Black will time travel to escape OR block with the bishop OR block with the knight OR capture with a black pawn (it doesn't matter). Then do the same white queen into the past move as in the normal solution to give checkmate. (Black can't do the same trick as the normal strategy of travelling back in time, because the only board she can reach that's further rewound has a check that can't be resolved by travelling onto it with the queen.)

Opening Traps V: Wait, are we sure this puzzle isn't about how we've actually lost, in fact? Things that don't work: On the top board, we can't capture the black queen with the white king since it's protected. We can't capture it with any other piece. We can't just go aggro obviously since we'd remain in check. We can't even run away, since the queen threatens cross-timeline checks, too. Therefore, an observation: The future timeline is ours to play on, and probably we can get a mate in one there? The solution: And in fact, we can - we have to send our black queen as far in the past as possible. There's only one tile to do so, and it simultaneously solves our check problem (by rewinding the present) AND gets checkmate (a defended queen checks multiple kings).

These puzzles take advantage of a subtlety in the rules for how checkmate works - if you're stuck, try reading it more closely and giving them another shot! Once you realize the edge case, you're set to solve these two puzzles.

Tricky Checkmates I: This is weird. What am I meant to do here? I can obviously check a past King by just moving a Bishop orthogonally adjacent to the King (we learned this trick in Bishop Tactics), but the present King can just capture it. Why does it matter that there's a second timeline with not much in it? If I move a pawn from it to the timeline that 'matters', then it's just a waste of a move. Am I missing something? Yes - check the Rules carefully, especially the definition of checkmate and how a player loses the game. - Think about this: What happens if a player can't make enough legal moves to advance the Present? - Well, let's try it. The only piece the AI can move on the bottom board is the pawn, so just block it with a pawn and do something irrelevant on the top board... But the King can just move across boards. - Wait! But the only reason why it can move across boards is because it doesn't need to capture the Bishop delivering past King check anymore! - So let's simultaneously deliver check on the top board and block the pawn on the bottom board. Success! The rule we just learned is 'if our opponent is in check and can't make enough moves to advance the Present to their opponent, they lose the game, even if the check can be resolved'.

Tricky Checkmates II: Now how do I solve THIS? Based on how Tricky Checkmates I was solved, it seems obvious that I have to use the Knight to deliver past check (it doesn't matter that the pawn will capture it back, then do something on the bottom board so there's no legal moves. But this time there's TWO unblocked pawns. What do I do? - If I can't block BOTH pawns, maybe it's a red herring and I should do something else? - Well, wait, now I'm noticing that attacking the black King with the Knight isn't my only move - I can also do it with the Bishop! - Yes, that seems to be it - if I do just one check on its own the King can respond to it with a capture, but if I do both at once, both the Past AND Present Kings are threatened at the same time, and that's too much to respond to! Clever, and entirely unlike the previous puzzle. - On +0L, move Bishop b2 to d4. On -0L, move Knight b1 to d2.

Tricky Checkmates III: Wait, what? Ideas that don't work: I can't just move the queen to check the king, since the king can capture or move. Moving from one present to the other also seems boring. Observation: I probably need to do something clever, like make a third branch or simultaneous check+stalemate. After all, it's TRICKY Checkmates. One last hint: Why would there be a pawn if it wasn't useful for something? The solution: Move the queen 2 east, then move the pawn 1 timeline north (forming a third branch. Why does this work? Because the white queen in the bottom timeline defends the white queen in the top timeline - so black can't capture it. (If you moved the white queen 3 east instead, then it wouldn't be defended and it could just be captured.) (If you moved the white queen 1 north 1 east or just 1 north instead, then both black kings have safe tiles to retreat to.) Since the top timeline white queen also attacks past kings and black can't rewind the present, it's mate! By cloning your queen into a new timeline, it was able to defend itself - tricky indeed!

Another puzzle that only works because of a subtlety in the specific rules for 5D chess.

Advanced Branching I: So the problem here is that I'm up on timelines and the present is really far back. - I seemingly can't use the future branch because my opponent doesn't have to play on it (including sending a knight from the present into the future), I can't send anything from the future to the present, and if I make a new timeline it's inactive and my opponent is not obliged to play on it.
I can threaten check with the knight, but the king can just escape, and it doesn't seem like any move I make in the future can matter since my opponent isn't obliged to respond to it (and the state as it exists doesn't threaten enough tiles to matter).
Threatening with queen is even worse, knight just takes and it's unthreatening.

Hmm...

Okay so since this is Advanced Branching, maybe I need to make a branch that, if it DID become active, would mean my opponent was checkmated. Am I smart enough to figure that out? - So I have to commit check in the present (presumably with the knight), and do something with the queen in the future that would threaten check if the king escaped by branching. - Yes, that is the solution! (Specifically, the Queen has to threaten the King in the past in a new inactive timeline and the Knight has to threaten the King in the present. Now if the AI tries to escape by branching the king, the Present recedes and checkmate is presented in the formerly inactive branch.) Cool puzzle!

Advanced Branching II:What big brain shenanigans await me in the new last puzzle? Things that don't work: In the top timeline, I can move the bishop to deliver check, and the knight kind of defends it (2 north 1 past), but too slow to actually work - the white king can just capture the bishop. - I could move the top timeline bishop 1 timeline-south 1 north to deliver check on the new branch, but white can easily deal with it. - Observation: Well, it's Advanced Branching - I probably have to use both my boards and spawn timelines to do something surprising. What possibility space should I therefore explore? In particular: I can't force my opponent to play on the future timeline, but I can spawn a new branch from it. What can I do that helps me? - Funny obstacle: If I branch twice as far back as possible, the white bishop in the topmost timeline can threaten check on a black king 3 timeline-south 3 south. Ouch! I even got mated in one by that bishop. I lost to the puzzle AI -w- https://cdn.discordapp.com/attachments/715057331142000640/763358329472548894/unknown.png

Hmm...

Yet another obstacle: Even if I arrange my bishops on the two new branches such that I'm not branching into check, my opponent might be able to get out of whatever I do and mate me back: https://cdn.discordapp.com/attachments/715057331142000640/763358918595837962/unknown.png

I think I need to figure out what my goal *is*, besides doing something big brain.

I feel like my goal is: Using the future timeline to branch to make a buffer, then using the present timeline to set up a check that white can't do anything about BECAUSE of my extra branching efforts. But e.g. this doesn't work: https://cdn.discordapp.com/attachments/715057331142000640/763360629230272512/SPOILER_unknown.png But it WOULD work if the rook couldn't move to block, because the white king couldn't escape onto the nearby branch since there's an existing check there. So it feels close?

An observation: I haven't been thinking about attacks with the knight at all - so it could be to do with that. I can make a knight attack, but white just branches into the past from a different timeline and checkmates me, e.g. https://cdn.discordapp.com/attachments/715057331142000640/763361480548548628/SPOILER_unknown.png

One last hint: It is indeed an attack with the knight - and it is 200 IQ.

The solution: On the future timeline, do any legal move 1 turn into the past. Then, on the present (topmost) timeline, move the black knight 2 north 1 timeline-south. The reason why this works is because you've positioned the knight on this new branch perfectly to check a past white king across The Void 2 timeline-north 1 north. It's protected, so can't be captured by the white king - white can't capture it with any other piece - and white can't rewind the past from this position (it looks like white could rewind it from the top timeline, but both king moves that could do it are into check - in practice, white uses the white bishop in the 1st new branch to rewind and checkmate you, but you pre-empted that). It doesn't matter what the state of the first branch you made is, it only exists to create the gap to line up the knight attack. (In particular, if you DON'T make that first branch, it is still check, but it checks a PRESENT king. So white can rewind time, refuse to play on the present board with the checked king and checkmate you back.) Brilliant!