That's Illegal! Trivia Quiz

Answer: The king can only move one square

The king can move one square in any possible direction - horizontally, vertically and diagonally. Ben mixed up the king and the queen, a common mistake among beginners. Grace lets him take the move back and he moves the king one square diagonally instead.

His new move is still not a good idea: the king needs to reach safety when there are still lots of pieces on the board, and it moves towards danger by going forwards, closer to the center of the board. We'll see how this causes trouble for Ben in a few questions' time...

Answer: Yes

Beginners learn that knights move in an "L" shape, but that can be an "L" in any rotation (or mirror image). Here, the move is more like a "г", which is at least a letter of the Russian alphabet. Ben did well to spot this move, because forgetting that knights (or other pieces) can move backwards is a common beginner's mistake.

Another source of confusion is that the knight cannot make the marked move without crossing over another piece - it would either pass across the Black pawn or the White pawn. However, knights are able to jump over other pieces, one of the things that makes them unique.

Answer: No

A pawn can only move forwards two squares when it has not moved at all before - in other words, when it is still on the second rank (or seventh in Black's case). Ben was confused because he thought a pawn capture did not count for this rule, but it does. With an earlier move of his h-pawn, however, he's demonstrated that he knows the rule is optional, and that a pawn can still choose to move forwards one square even when it could move two squares instead.

Though not close to the worst of his problems, Ben's pawn structure - with two pawns both on the c-file - is not ideal. Called "doubled pawns", these two pawns are not able to protect each other, as pawns can only capture diagonally, not forwards.

Answer: Pin

Moving the pawn is illegal because you are not allowed to end your move with your king in check. Grace, though, has no reason to want to move it forwards when she can instead capture Ben's bishop diagonally, which she does.

Pins can be created with any piece that can capture by moving multiple squares in a single direction: the bishop (diagonally), the rook (horizontally and vertically) and the queen (diagonally, horizontally and vertically). Here, bishop "pins the pawn to the king". You can also pin a piece to something other than a king - usually something of importance, like a queen. In this case, the pinned piece can legally move, but doing so is not generally wise.

To address the wrong answers: a "skewer" is when a piece attacks two pieces in a line, like a pin, but the piece in front is at least as valuable as the one behind it. For instance, you might skewer two rooks with your bishop. A "fork" is when one piece attacks two pieces at the same time. An "exchange" (or "trade") just refers to pieces of equal value being removed from the board - for instance, if Ben captures Grace's bishop and then Grace captures his bishop.

Answer: The king is on the wrong square to castle

Castling has lots of conditions: the king and rook must never have moved and there must be no pieces on the squares between them. In addition, the whole path must be free from checks - the king cannot be in check or end the turn in check (as always) and, most often forgotten, cannot move through a square that would put it in check (though the rook can move to an attacked square).

In Ben's case, three of these fives rules have been broken! He only has one legal move in the position, as he still needs to escape check, and it's not a great one...

Answer: Black (Grace)

In most cases, if your clock runs out of time, you lose by default. The only exception is when there is no way you could possibly win the game if it continued - for instance, if you only have a king and your opponent has a king and a queen. In these cases, the game is declared a draw.

Here, Grace wins by timeout, though she had a winning position anyway. White has to move his king one square to the right to escape check. Black might bring her light-squared bishop into the attack and deliver checkmate fairly quickly.

Particularly in games with quick time controls - called "rapid", "blitz" or "bullet" depending on the precise time limits - the clock becomes part of the tactics, and you need to decide which moves are worth spending more time on. Playing speedily to make your opponent run out of time ("flag") is generally acceptable, even if you are in a losing position: maybe your opponent only reached a winning position in the first place because they spent more time than they could afford.

Answer: No

If you're playing with one chess set, and the queen is still on the board, you just have to make do with what you have. Often an upside-down rook will work, or you can keep playing with the pawn and just remember that it is a queen. In serious games, there should be spare queens either at the board or with the arbiter.

In this case, Grace doesn't need to promote to a queen - a rook will do the job just as well. She sees that there's checkmate in two moves: by promoting to a rook (for instance), she puts the Black king in check. Ben's only move is to interpose the Black rook (move it in the way), and because of White's bishop, when the White rook captures the Black one it will be checkmate.

Answer: Grace can make any move she likes

The touch-move rule is designed to stop players picking up pieces, waving them around and then deciding not to move them. However, until you've let go of a piece, you can change your mind about which square to move it to. When you touch a piece that can't be moved, there's no punishment - you can just make your move as normal. The same is true of accidentally brushing against a piece. But it's good practice to keep your hands far away from the board until you've decided on your move, and then to make it quickly and cleanly.

In this case, Grace just had a moment of madness, and she delivers checkmate in two moves as we discussed in the previous question. Her 2-0 victory leaves Ben in awe of her, and he decides to watch her play against another Grandmaster.

An exception to the rule is when adjusting pieces - for instance, if a pawn is straddling across two squares. In this case, you can say "j'adoube" (French for "I adjust") and then centralize the piece.

Answer: It can only be made on the first move where it is possible

The move marked in green would have been legal (and a good move!) had Grace played it immediately after Garry moved his g-pawn. En passant is when a pawn captures another pawn as if it had just moved forwards by one square. Here, the Black pawn would end up on the marked square (g3) and the White pawn would be removed from the board. The rule was introduced at the same time that pawns were allowed to move forwards twice on their first turn - in the late medieval era.

When walking around the room to observe other players' games, Grace can usually tell who is winning, and en passant is one of the only things that can throw a wrench in the works. She can work out whose turn it is by seeing whose chess clock is counting down, but without seeing the last move played, she can't always work out if en passant is possible. Castling is the only similar case: it is not always possible to tell if the king or rook have moved before, which would rule out the option to castle.

Answer: No

Threefold repetition - when the same position occurs three times on the board - is a way the game can be drawn, but only if one of the players chooses to claim it. To claim the draw, you must either call an arbiter over and announce that you are about to make a move that will cause a threefold repetition, or you must call an arbiter over and announce that your opponent has just caused a threefold repetition.

Since Garry just moved, and produced a new position with his move, Grace has no right to claim threefold repetition. If the same position had occurred five times (fivefold repetition) then it would be a draw automatically, but that's not the case after three times.

Grace and Garry play on but the game eventually ends in a draw anyway - such is the nature of chess at a Grandmaster level. Nonetheless, Ben Boardgame comes away having learned a lot about how to play well. He was particularly struck by the fact that even Grandmasters sometimes need 15 minutes to decide what move to make!