20 votes
Accepted

Could two kings force checkmate against a lone king?

If these are two real kings, it is not possible. This is because one requirement of checkmate is that the black king is in check which cannot be achieved with any of the white kings, since it would ...
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  • 20.3k
18 votes

Could two kings force checkmate against a lone king?

A King and a Man (or commoner; i.e., a non-royal King) can mate a lone King. The longest distance to mate on a standard 8x8 board is 18 moves. The result quoted above was obtained by H.G. Muller in ...
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15 votes

Was there a chess piece—elephant, knight or rook—rendered as a being looking into two directions?

In shatranj, the game out of which chess developed, the rukhs (rooks) are portrayed a bit like the way you describe. That Wikipedia article contains this illustration of a 12th-century Iranian ...
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  • 5,562
13 votes
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How to solve this puzzle of Martin Gardner?

According to the FIDE Laws of Chess: 1.4 The objective of each player is to place the opponent’s king ‘under attack’ in such a way that the opponent has no legal move. 1.4.1 The player who achieves ...
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  • 74.6k
10 votes

Was there a chess piece—elephant, knight or rook—rendered as a being looking into two directions?

The Janus-Springer set includes such a knight.
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8 votes
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Fairy chess: KNNvK

The Wikipedia page on the Nightrider contains an example from T. R. Dawson, published in the British Chess Magazine in 1925, where a king, knight and nightrider force a mate against a lone king. I ...
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  • 23.8k
8 votes

Was there a chess piece—elephant, knight or rook—rendered as a being looking into two directions?

I don't really know the history; just was curious and will be presenting some of my google findings here. First, I came across Rook (chess) heraldry on Wikipedia: Chess rooks frequently occur as ...
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  • 181
6 votes
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Queen with Knight capabilities

Are there any obscure chess variations where this is allowed? There are. One name for the queen+knight hybrid piece is the Amazon. As noted in the Wikipedia entry on the Amazon piece I just linked to,...
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  • 23k
6 votes

Controversy over the Xiangqi cannon piece?

The character 砲 (pào) gives a significant clue: compared to 炮, which is homophonous, the radicals of these characters are different. 砲 uses the 石 radical, which means stone, and 炮 uses the 火 radical,...
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5 votes

Would a piece that moved like a king – but could be captured (and could be moved en prise) – be considered a major or a minor piece?

This piece is widely used in different fairy chess variants. It appears under several names, including Commoner, Guard and Man / Mann. While the table in the Wikipedia article also linked to in @...
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  • 23.8k
5 votes

What is the maximum DTM with K+J vs K?

I make it 21 moves, but it's quite likely that my home-made Python code (too long and messy to post here!) has mistakes, so please take this with a grain of salt. I get 112 positions which require 21 ...
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5 votes

What is the maximum DTM with K+J vs K?

I don't know the exact answer for the 10x8 board (used e.g. in Capablanca Chess, where your Janus is called the Archbishop), but I have something that could get you well along toward an exact answer, ...
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  • 23k
5 votes
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Amazon vs Chancellor endgame

This is a great question and a fun problem to mull over. Indeed the way it's written on wikipedia one gets the impression that amazon-vs-empress fortresses are trivial and easily attainable for the ...
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  • 11.8k
5 votes
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Would certain checkmates be possible if the king could move into check?

You could force a checkmate with two knights and a "king". Because the "king" does not fear being taken, it can move directly in front of the opponent's king, if it is protected by a knight. All it ...
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  • 15.1k
4 votes
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Chess variants-Anyone recall the name for one that has a "superpiece" with the movements of the queen and knight?

According to the Wikipedia variants page, there does not seem to be a variant with a specific name, but there are several variants that use the queen-knight hybrid, which is called an Amazon (...
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  • 31.9k
4 votes
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What is the maximum number of squares 8 queens and 8 nightriders can attack on a 16x16 board?

It's possible to attack all squares. Q - queen N - nightrider Yellow background - attacked only by a queen Red background - attacked only by a nightrider Orange background - attacked by pieces of ...
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  • 258
4 votes
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Fairy endgame statistics for KDDDDvKN (D=dabbaba; '2,0' leaper)?

I was unable to generate data for exactly what you want, but I managed something with a restriction to 6x6 board. I think it's reasonable to assume that it doesn't make a big difference from 8x8 for ...
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  • 258
4 votes

Is this a sound elephant offer?

It's not a sacrifice, it's a trade after 1. Gxc2 G*b3 and taking the elephant on a3 next. On the other hand, since doubutsu shogi is strongly solved, you can use an engine/tablebase (e.g. https://...
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  • 4,830
4 votes

How to solve this puzzle of Martin Gardner?

Ok, I think I got it. Your first move is Nc3-Nb5, threatening Nxc7 and Nxe8 in its next move, and since Black can't move their King they just can't prevent check mate. EDIT: just to make it clearer, ...
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  • 1,613
4 votes
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Material value of the Berolina pawn

According to Gnu, which has a page dedicated to Berolina chess, the value of the Berolina pawn is the same as in standard chess, = 1. This is unsatisfactory because they give no explanation of how ...
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  • 74.6k
4 votes

Would a piece that moved like a king – but could be captured (and could be moved en prise) – be considered a major or a minor piece?

I haven't heard of that definition being used for a major piece, but it's a neat observation. Such a piece (call it X) should be able to force a checkmate in a K+X vs K situation. Say White's pieces ...
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3 votes

Would a piece that moved like a king – but could be captured (and could be moved en prise) – be considered a major or a minor piece?

That is an interesting distinction theory. Although this king-like piece could deliver checkmate with the help of the king, I've always considered the difference to be based on the value of the piece....
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  • 5,123
3 votes

Would a piece that moved like a king – but could be captured (and could be moved en prise) – be considered a major or a minor piece?

The king is worth about 4 pawns if its loss didn't lose the game, which means it's neither a minor or a major piece, but something in between. (Major pieces like the rook is worth 5+ pawns; minor ...
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  • 21.4k
3 votes
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Marshall vs. Queen Endgame

Since my Stockfish fork for fairy chess variants already supports Almost Chess, I added Sort of Almost Chess with both sides having all promotion options (which is what you seem to imply in your ...
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3 votes

Could two kings force checkmate against a lone king?

Non-royal king is a combination of [0,1] leaper (wazir) and [1,1] leaper (fers) and in fairy chess called a erlking. About erlking, see my book Fairy chess endings on an n x n chessboard (2017), page ...
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2 votes

Fairy chess: KNNvK

See my book Fairy chess endings on an n x n chessboard (2017), p. 345 and 414. The ending of king + two nightriders against bare king on board 8x8 is won for the stronger side and the longest win has ...
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2 votes

What is the maximum number of squares 8 queens and 8 nightriders can attack on a 16x16 board?

This is my best attempt thus far, which I believe attacks 236 (all but 20) squares. I used the staircase solution for 8 queens on the central 8x8 region in order to consequentially fully cover the 4 ...
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2 votes
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Is it possible for the hopper/locust to jump over unmovable squares?

Your question: If a board with unmovable squares, such as Chessence, has a Cannon on a1, and an enemy piece on a3, can the Cannon jump over the unmovable square (a2) and capture the target? Relevant ...
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  • 1,644
1 vote

An online dictionary of fairy chess pieces indexed by move

There is the Wikipadia page "Fairy Chess Piece" with a table of popular and well known fairies. You can re-order the table by Betza notation or Parlett notation to get an ordering by move ...
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