Rules
Welcome to Chess 13: Epoch. It is chess on a bigger board, with new pieces and one new idea that runs through all of them.
The board is 13 by 13, only two pieces move the way you already know, the king and the queen, and every piece in your army has two versions, enhanced and restricted, decided by where it stands. That last one takes the longest to get used to. Underneath it is still chess. You still have a king to protect, you still win by checkmate, and pawns still promote.
Everything you need is on this page, in the order you need it. First the board, then the command square, then each piece on its own, then promotion, then the ways a game ends.
Read this first
You should know normal chess before you start. This page does not teach you what check means, how a rook moves, or why castling exists. It only tells you what is different here, and it does that on almost every line.
If chess is new to you, go and learn that first. An hour with any beginner guide is enough. Come back after that and this page turns into a short list of differences instead of something you have to decode.
If you already play, take it slowly anyway. There is a lot here. Read the command square part twice, because everything after it depends on it. And do not try to hold all of it at once. Most people come back to this page during their first few games, and that is normal.
The Board
Thirteen squares wide and thirteen deep. Files run a to m, ranks run 1 to 13. Each side owns 26 pieces: a full back rank of nine kinds, and thirteen Legionaries in front of it.
Your back rank is rank 1, your Legionaries stand on rank 3, and rank 2 sits empty between them. Black is the mirror of that, on ranks 13 and 11.
Because 13 is odd there is a true middle rank, rank 7, and both sides are six ranks away from it. Legionaries cannot walk past it in one move, so that is where the two armies first meet. The square in the middle of it, g7, is worth remembering. It is the command square, and the next section is about what standing there does.
The Command Square
This is the one rule that has nothing like it in chess, so read it carefully. Every piece you own has two versions, enhanced and restricted. Which one you get depends only on how far that piece is standing from your own Marshal.
- Marshal on g7. Your whole army is enhanced, no matter where each piece is standing.
- Marshal anywhere else. Every piece within four squares of it is enhanced. Distance is counted the same way a king moves, so one diagonal step counts as one square, and the zone is a 9 by 9 block with the Marshal in the middle. That is 81 squares out of 169, or fewer if the Marshal is near an edge of the board. Every piece further away is restricted.
- Marshal captured. Your whole army is restricted for the rest of the game, unless a Legionary promotes into a new Marshal and the zone comes back.
The zone only affects your own pieces. Your opponent's pieces are enhanced or restricted by their own Marshal, not by yours. Two of your pieces ignore the zone completely, the Pope and the Emperor. They have one version only, inside the zone or outside it.
A piece is read on the square it starts from, not the square it lands on. If it is inside the zone at the start of the move, it moves as the enhanced version, even if the move takes it outside the zone. It becomes restricted on your next turn.
The zone covers less than half the board, and it moves with the Marshal. If your attack goes deep into their half, or out to an edge, those pieces are no longer in the zone and become restricted. To keep them enhanced you have to move the Marshal forward too, and if the Marshal is captured your whole army stays restricted. So on most turns you have to choose: use the Marshal as an attacking piece, or keep it where your army needs the zone. It moves like a queen, so you can change your mind quickly.
The Pieces
There are nine kinds. Only two of them move the way they do in chess, the Pope and the Emperor. The other seven are new, and each one is written out below in both versions, enhanced first, then restricted.
They are in order from the easiest to the hardest, so read them from the top the first time.
Legend
- The green square is the piece being explained.
- A green dot is a square the piece can move to.
- Red corners are a square the piece can move to only when the move takes a piece.
- A red square is a piece caught in a blast.
- A red arrow shows the piece attacking an opponent's piece.
- A blue arrow shows the piece defending a piece of the same colour.
- The badge behind a piece means it is enhanced.
- The purple square is the command square.
These marks belong to this page only, to make the diagrams easier to read. In a game you may mark the board however you like.
Herald
→
The bishop of this game, with one extra move: a single step straight up, down, left or right. That step is what lets it change square colour, so it is not stuck on one colour for the whole game the way a bishop is.
Enhanced
Diagonals with no limit, for moving and for capturing. The straight step can capture as well.
Restricted
Diagonals up to six squares, for moving and for capturing. The straight step is still there, but it cannot capture.
Its diagonal reach is the same whether it is moving to an empty square or capturing a piece.
Sentinel
→
The rook of this game. Straight lines only, and the path has to be clear. How far it goes depends on whether the move captures: a capture reaches further than a quiet move, so an enemy piece far down the line is still in range.
It slides along a rank or a file while the line stays clear. Two of its moves carry a condition: a square too far for a quiet move is still open if the move captures the piece standing there, and your own pieces let it through while it heads towards your Marshal.
Enhanced
Six squares on a quiet move, no limit when it captures, and it passes through your own pieces towards your Marshal.
Restricted
Three squares on a quiet move, six when it captures, and any piece blocks it.
Towards is measured one axis at a time, not by standing on the same line. Along a rank it is the direction that closes the distance in files, along a file the direction that closes the distance in ranks. With the Marshal on d3, a Sentinel on a1 heads towards it both east and north.
Once it has passed through it can no longer capture, so the move ends on the last free square before the next piece. A square that far cannot be moved to on a quiet move either, so the only way to reach it is by capturing the piece standing there.
It reaches it only by capturing
It passes through, then cannot capture
A far square is open only to a capture, and a line that has already gone through your own piece cannot make one at all.
Templar
→The knight of this game. Every move is a leap, so the pieces in between do not matter, and the piece it lands on is the piece it captures.
Enhanced
Two leap shapes, three squares one way and two the other, or two squares one way and one the other, which is the knight leap of chess.
Restricted
One leap shape only, three squares one way and two the other. The knight leap is gone.
The leap it gains is the shorter one, so a restricted Templar always lands far from where it started.
Legionary
→
The pawn of this game. Forward only, never back, and anything in front of it holds it where it is.
Rank 7 is the middle rank. Below it a Legionary moves straight forward to any empty square up to rank 7 and no further, which is four squares in all from where it starts the game. If something is in the way it stops earlier and finishes the advance on a later turn.
Advance below rank 7
The dots stop at rank 7 even though the file ahead is empty, so the first stretch never carries it past the middle rank.
Once it stands on rank 7 or beyond, the limit is gone and a shorter step takes over. How long that step is depends on the zone it is in.
Enhanced
From rank 7 onward, one or two squares forward each move.
Restricted
From rank 7 onward, one square forward each move.
Both boards start from the same square, so the enhanced zone gains a tempo, and either way capturing is one square diagonally forward like a pawn.
En passant works here too, and only against one move: the advance that goes straight from a Legionary's own starting rank to rank 7. A Legionary attacking a square that advance crossed may capture it as though it had stopped one square short, on the move immediately following. An advance that begins anywhere else gives nothing.
White advances to e7
Black captures en passant
The right is gone the moment it is not used: play anything else and that square can no longer be captured.
A Legionary that reaches the last rank is exchanged for a piece your own side has already lost. The full rule is under Promotion.
Mage
Moves one square in any of the eight directions, and two squares while enhanced. The two-square move is a leap, so a piece standing on the square in between neither stops it nor is captured. The square it lands on must be empty.
What is different is how it kills: a Mage never captures a piece by moving onto it. Instead it blasts everything standing next to it.
Enhanced
One square each move, or two as a leap, and the blast destroys enemy pieces only.
Restricted
One square each move, and the blast destroys your own pieces in the ring as well.
The eight squares around the Mage are its ring. A turn is either a move or a blast, never both. When it blasts it stays where it is and comes through its own blast unharmed, and it may blast again the turn after.
A blast needs at least one enemy piece in the ring. An empty ring is not allowed, and neither is a ring holding only your own pieces, because either one would be a wasted turn.
Assassin
It travels the same eight directions as a queen, straight and diagonal, and the path has to be clear.
What is different is the capture: an Assassin never ends on the square of the piece it captures. It passes over that piece and lands on the square immediately beyond, and the piece it passed over is captured where it stood.
Enhanced
The line has no limit. It moves as far along it as the path stays clear, and it captures a piece standing anywhere on that same line.
Restricted
The line is cut to six squares. It moves up to six, and it captures only a piece close enough that the whole capture stays inside those six.
Wherever it can move it can also capture, as long as the square beyond the piece is still within its reach.
When it captures, the square behind the piece must be empty and must not be attacked. The condition is on the capture alone, a quiet move lands wherever the line is clear. It captures one piece a move.
The square behind is occupied
The square behind is attacked by the opponent
Neither piece under attack here is defended, and neither can be captured. The square behind one is occupied and the square behind the other is defended, and either alone makes the capture illegal.
Where the board ends there is no square behind, so a piece on the far rank cannot be captured from in front, and the Assassin has to come at it from another direction. The corners are the exception, having nothing behind them at all: a piece on a corner is captured the ordinary way, with the Assassin ending on the corner, which still must not be attacked.
Capturing on a corner
The capture is not allowed
On a corner the piece it captures stands on the square it lands on, so the only condition left is that nothing attacks that square.
Marshal
The piece your whole army depends on. It is what turns your other pieces enhanced, and what it can capture depends on the rest of your army.
Each of your pieces looks at where your Marshal stands to know which version of itself it is. On the command square it enhances your whole army at once, wherever the pieces are. Anywhere else it enhances only what stands within four squares of it, sideways, up and down or diagonally, and everything further out is restricted.
On the command square
Four squares in every direction
Against the edge
In a corner
The zone is a square block, and the edge of the board cuts whatever falls outside it, so the same Marshal covers far fewer pieces from a corner than from the middle.
Moving is the easy half: any distance along a rank, a file or a diagonal, for as long as the path in front of it is clear.
Eight lines, any distance
Nothing holds it back here, and no square is out of reach on an open board. Every limit it has falls on the capture instead.
Capturing is the half that is held back. The Marshal only captures a piece one of your other pieces is already attacking, and without that the capture is simply not available.
The Herald already attacks it
Nothing of yours attacks it
The line to the Sentinel is the same either way. What decides the capture is whether anything else of yours is aiming at that square.
The Mage and the Assassin are the hard ones to read. Both attack in their own way, and it takes a second look to tell whether a piece is attacked by them. In the two positions here it is, so the Marshal may capture.
The Mage attacks everything next to it
The Marshal captures though the Mage cannot blast
The Marshal can capture, the square behind is only attacked
The Marshal cannot capture, the square behind is occupied
A Mage attacks every square around it, so anything next to it is open to the Marshal.
An Assassin attacks along its line as soon as the square behind the piece is empty. If that square is attacked, the Marshal can still captures and the Assassin cannot: that is the Assassin's own problem. If the square is occupied there is no attack, and neither of them can capture.
Riposte
The Marshal has one special right of its own. Lose a piece on a square it has a clear line to, and for one move it captures on those lines with nothing of yours attacking the piece. The right holds only on the move immediately following, and after that the Marshal again captures only what your other pieces attack.
Watch the square the piece falls on. The Marshal sweeps its eight lines outward, and the capture only counts if that square is one of them. Anything standing in between, yours or the opponent's, cuts the line short and no right appears.
The capture triggers the riposte
The capture does not trigger the riposte
The capture is the same on both, and so is the diagonal it happened on. All that changes is whether the Marshal's path to that square is open.
The riposte is not always triggered. A Mage that kills your own piece in its ring gives you nothing, since only a capture by the opponent creates the right. Anything standing between the Marshal and the square where your piece died cuts the line as well, and an Assassin that lands there does that to itself.
The blast comes from your own Mage
The same blast comes from the opponent
The Assassin lands on the line and cuts it
The Assassin lands where the Marshal can capture it
A Mage blasting its own never opens a riposte, whatever the Marshal sees. The Assassin is safe only when it blocks the Marshal's path to the square where the capture happened. If it does not, the Marshal may capture it, and this is the one time an Assassin can be captured right after capturing, since the riposte creates an attack the landing square did not have before.
Emperor
→
The queen of this game. It travels along a rank, a file or a diagonal as far as the line is open, and captures the first enemy piece on that line. The Marshal's zone does not touch it, so it plays the same everywhere on the board.
Every line, any distance
Every square it can move to is a square it can capture on, so the only thing that shortens a line is a piece standing in it.
Dormancy
The Emperor does not start the game in play. While your Marshal is alive it stands dormant: it cannot move, it cannot capture, it guards nothing, and nothing on the board can remove it, a blast included. It still fills its square, so a line behind it stays closed.
Two things bring it into play: your Marshal is captured, or the Emperor stands under attack when your turn begins. Only the start of your turn counts, so an attack that comes and goes during the opponent's turn changes nothing. Once it is in play it stays that way for the rest of the game, and a new Marshal does not make it dormant again.
The attack arrives down the file
Which piece does it changes nothing. A leap from a Templar, a diagonal, the ring of a Mage, any of them counts, and what decides is only whether the square is attacked when your turn opens.
You can open the line yourself. Move one of your own pieces off it and an enemy line falls on your Emperor, a discovered attack you set up against your own piece. It costs you a move, and the opponent chooses: withdraw the attacker, or leave it standing with a defender behind it, so your Emperor comes into play already attacked and has to move or be captured.
Your own Mage steps off the line
The Marshal steps down and the line still holds
Opening the line on your own move settles nothing, because the reading waits for your turn to start. What counts is the attack still standing after the opponent has moved. Coming into play is not the same as being safe, since it arrives with that line still aimed at it.
A dormant Emperor guards nothing, so the square in front of it reads as free and an Assassin may take a piece there. The same landing leaves the Emperor under attack, and once your turn opens it is in play and can capture the Assassin where it stands.
The Assassin lands on the line to the Emperor
The capture was legal when it was played, and it is the Assassin's own arrival that opened the line to it.
Pope
→The king of this game. One square in any of the eight directions, and it captures the same way. The Marshal's zone does not affect it, so it plays the same wherever it stands. It is the piece the game ends on, so it is never traded and may never be left under attack.
One square in every direction
The eight squares around it are its whole reach, and each one is open to a quiet move and to a capture alike.
Castling
Castling works as it does in chess, except the partner is a Sentinel and the Pope travels three files instead of two. It is one move, to the left or to the right. Neither piece may have moved earlier, every square between them has to be empty, and the Pope may not start, cross or finish on a square the opponent attacks.
Where castling puts the Pope
The two dots stand three files out from the Pope, and each Sentinel finishes on a square the Pope crossed on its way there, e1 on the left and i1 on the right.
Check
Check works as it does in chess. A piece attacks the Pope, and the reply has to answer it. Three pieces are read differently, the Mage, the Assassin and the Marshal, since each of them attacks on terms of its own.
A Mage never captures by moving, so the check is the square it stands on. Next to the Pope is already check, since the blast on its next turn takes it where it stands. A restricted Mage with its own Pope in the same ring gives none, because that blast is not allowed and nothing is threatened.
The Mage stands next to the Pope
Its own Pope shares the ring
The Marshal turns the Mage enhanced
The Mage stands on the same square in all three. What decides is whether its own Pope shares the ring, since the blast that would deliver the check is the blast it is forbidden to play. Bring the Marshal close and the Mage is enhanced, so the blast passes over its own Pope and the check stands again.
For the Assassin the check is on the square behind the Pope. There is none if that square is occupied, or if the Pope's side attacks that square, and on the far rank there is no square behind at all. Only on a corner does it land where the Pope stands.
The square behind the Pope is occupied
The square behind the Pope is attacked
The Pope stands on the far rank
The Pope stands on a corner
What decides the check is the square behind the Pope, never the line the Assassin stands on. As long as that square is empty and the Pope's side does not attack it, an Assassin far down the line threatens as much as one standing beside the Pope. Only the corner asks for no square behind at all, and there the Assassin ends where the Pope stood.
The Marshal is the opposite case. Against an ordinary piece it captures only what one of its own pieces already attacks, but the Pope is exempt, so a clear line to it is already check.
The Marshal checks on its own
The Marshal has no second attacker on the board and the Pope is attacked all the same. The Pope has to step off the line, something has to block it, or the Marshal has to be captured.
A dormant Emperor cannot be captured, but it can be attacked, and attacking it wakes the Emperor on the opponent's turn. If it attacks your Pope from where it stands, the Pope falls that same turn, so the move never appears.
One square of the line is missing
The diagonal is clear the whole way, so nothing on the board blocks the square that is missing. What takes it out is the file the Emperor and the Pope share, since a Herald landing there wakes the Emperor onto the Pope.
Promotion
A Legionary that gets to the last rank is traded for one of your own captured pieces. Nothing else is on offer, so neither side ever holds more of a type than it began with, and the Pope can never be taken.
Where the piece was captured decides who can claim it. A captured piece counts on the file it stood on, and a Legionary on the last rank claims it only from that file or the one to either side. Say you lose a Sentinel on file c. A Legionary arriving on b13, c13 or d13 can take its place, and one arriving on e13 cannot.
A Legionary that arrives while a place is already open trades on the spot, inside the same move, with no turn spent on it. If two places are open across its three files, you choose which one to take. You cannot arrive and decline, because the move exists only as the trade.
With no place open it stays on the last rank as a Legionary, and it can wait there for the rest of the game. The right never runs out. Once one of your pieces is captured on one of its three files it may take that place, and this time the trade is your whole move.
Trading into a Marshal puts the command zone back on the board, and trading into an Emperor skips the dormancy.
Piece Values
Chess counts its own pieces in points, a pawn at 1, a knight or bishop at 3, a rook at 5 and a queen at 9. That is the scale everything here is read on.
| Piece | Value | |
|---|---|---|
| Pawn | 1 | |
| Knight | 3 | |
| Bishop | 3 | |
| Rook | 5 | |
| Queen | 9 | |
The pieces of this game sit against those numbers. Most of them carry two, since the same piece is worth more enhanced than it is restricted.
| Piece | Enhanced | Restricted |
|---|---|---|
| Pope | ∞ | |
| Emperor | 15 | |
| Marshal | 13 | |
| Assassin | 10 | 7 |
| Sentinel | 9 | 6 |
| Mage | 8 | 5 |
| Herald | 7 | 5 |
| Templar | 7 | 5 |
| Legionary | 2 | 2 |
Both tables are judged by eye and nothing is calculated behind them. The 1, 3, 5 and 9 of chess is a convention rather than a measurement, and these figures are set against that convention the same way.
The Pope carries no number, since you never trade it and losing it ends the game. The Pope, the Emperor and the Marshal hold one figure across both columns, because the zone does not touch the first two and the Marshal carries the zone with it. The Marshal number leaves the command zone out, so capturing one is worth more than the table says, because every piece it was enhancing turns restricted.
The Result
White moves first, and the game is decided on the Pope. There are five results, and two of them do not exist in chess.
- The Pope is checkmated. The side that is mated loses, exactly as in chess.
- A side has no legal move and is not in check. That side wins.
- A move repeats the same position a third time. Whoever plays that move loses.
- The no-progress limit runs out. Draw.
- Neither side has enough material to mate. Draw.
The second result is the one that catches chess players out. Strip your opponent of every legal move without mating them and you are the one who loses. Chess would call that a draw. Here you have to keep a move available to them and then finish with mate.
The third is threefold repetition, and here it is not a draw. Whoever plays the move that brings a position up for the third time loses the game on that move. The move stays legal, it simply loses.
A position counts as repeated when every piece stands where it stood, the same side is on move, and the same castling, en passant and riposte rights are still open.
The no-progress limit
The game is drawn once neither side has made progress for long enough. Progress is a capture, a blast, a Legionary step or a promotion. Every turn without one adds a point to the count, and the next turn with one clears it. A turn is a move from each side, the way chess counts its fifty.
How many of those turns you are allowed is read off the board:
limit = 60 + 2 × (52 − pieces on board)
Mate takes far longer with two pieces than with twenty, so one fixed number would cut real endgames short and let a crowded middlegame sit still for far too long. The line runs between two points. At 52 pieces, the opening, it gives 60 turns, the fifty of chess stretched for a board 13 files wide instead of 8. At 3 pieces, a bare Pope against a Pope and one other, it gives 158, roughly double the longest mate this game is expected to need. Everything between sits on the straight line joining them, and that is all the 2 is: each piece that leaves the board buys two more turns.
Insufficient Material
This one is read narrowly for now. The game is drawn on it only when the two Popes are the last pieces on the board, and every other thin position is played out. Which material cannot force mate here has not been settled yet.
The Swap Rule
Whoever moves first wins more often. Records from other games put that edge somewhere around 52 to 56 per cent, and a wider board does nothing to remove it. This rule is how black is paid back for it, and it works without anyone having to measure how large the edge here is.
After white has played the opening move, black may take white's side instead of making a move. It is a single button, and it is only there on black's first turn.
Take it and the two players change places, with the game going on from the move white already played. Leave it and the game continues as normal.
Since black takes whichever side looks better, white has to open with a move that leaves the two sides about level. That covers everything moving first is worth, including reaching the middle rank ahead of black.