# 3D Chess - Stale NBA (kNight-Bishop Assault)

This is my very first puzzle. Any constructive feedback is more than welcome. Thanks!

## Introducing 3D Chess!

To make things simple for the first time, we are using a $$3\times3\times3$$ chessboard.

## First Things First - Notation:

Axes:

From top to bottom: i, ii, iii
From left to right: a, b, c
From front to back: 1, 2, 3

In other words (images) [sorry for my crude drawing :P]:

Example:

Kiia2

## Then - How Pieces Move

The puzzle this time only involves 3 kinds of pieces: Knight, Bishop, and King.

Note: Axes 1,2,3 can be any permutation of X, Y, and Z

Details:

1) Knight: (Axis1, Axis2, Axis3) = (0,1,2)
2) Bishop: (Axis1, Axis2, Axis3) = (0,n,n)
3) King: (Axis1, Axis2, Axis3) = (0,0,1) or (0,1,1)

## Now - The Puzzle

Given the configuration below, construct a stalemate (whatever side) in the minimum number of moves. White to move, and both sides take best moves.

## Note - Criterium

The one that has the solution with the currently least number of moves and $$moves \leq$$ 7 will get the green check. If needed, I will provide the number of moves in my solution in a hint.

Besides,

... though I wonder if it would be useful even if you use one :)

And...

Have FUN!

## Clarification - Best move

(no Checkmates allowed) > Check to Capture > Check > Capture > Attack > Normal moving > Defense from Check or Attack

Check to Capture: (can capture another piece in the next move since opponent is checked and that piece cannot be moved)
Attack: (can capture another piece should that piece not move in the next move)
Normal Move: (any other moves that is not Check to Capture, Check, Capture, Attack, or Defense)

Can anyone please explain the downvote? Thank you very much!

## More - Hints

usefulness level 1

My solution used 4 steps

• Requiring "best moves" implies that both sides try to win (or not to loose, if a win is impossible). This makes no sense if the goal is a stalemate for either side, as they could simply agree to draw. The only chess puzzle involving a stalemate and best moves is, when one side is loosing and a forced stalemate is the only way to draw the game. Commented Jul 4, 2019 at 14:55
• @Sleafar you'll see ;) Commented Jul 4, 2019 at 14:56
• Doesn't white win with best play here? After 1. Kiib2, the black king has no legal moves. No matter where the knight moves, it can't stop checkmate by the bishop on iib1 on the next move.
– Jafe
Commented Jul 4, 2019 at 19:07
• @jafe I think you are right. And this confirms what I have written above. Commented Jul 4, 2019 at 19:38
• @jafe sorry if you came up with a better solution, but this best move is calculated by the immediate effect instead of the effect to the whole game Commented Jul 4, 2019 at 23:48

Solution in

4

plies:

1.Baii2+ (fork, aka check&capture) Kxaii2 (capture)
2.Kci1 (normal move) Kbii2 stalemate

Remark: the alternative try

1.Bbii1+ (check) Kxbii1 (capture)
2.Kci3 (attack) Kbii2 stalemate

isn't allowed because

Black would have to play a check on move 2 with 2...Nbi1+.
And also because White 1st move would be a simple check and not an attack on the knight at the same time.

• why is white 1. forced? Commented Jul 10, 2019 at 7:19
• Because you maid captures mandatory is possible. But actually I just noticed that my first move is illegal, wK cannot move that way. Commented Jul 10, 2019 at 8:05
• this puzzle uses a greedy algorithm, i.e. for white 1. a check to capture is always better than a check (just an example) Commented Jul 11, 2019 at 10:55
• @DorianFusco : The wK cannot attack the bN on the second move because it is protected by the bK. Commented Jul 11, 2019 at 14:06
• Oh, right, I failed to consider this as a way to prevent the "Attack" rule from applying to us ! Then I believe this solution of yours is working, and is the only one that does it within 4 turns. Commented Jul 11, 2019 at 14:08