I have a game that's a 7-piece mate if we allow redundancies, but really a 5-piece mate if we omit the needless wQ and Ph2 or f2.
Game 7507220
A nice 5-er [not counting Pf7]
Game 7415663
- Joined
- 08 Apr 09
- Moves
- 20190
Hey SG,
i was looking for mates with one single piece-type, but with as many essential pieces as possible. Your rook set-up is good, but I think the queen set-up could be like a bishop set-up with maximum 5 essential pieces.
I'm not sure the position can be reached legally..
Your pawn set-up made me realize that an essential 9-piece (well yeah: pawn) checkmate positions is possible.
None of these pawns can be removed! It's obviously an illegal position by the way, because there are only 8 white pawns in a regular game.
Originally posted by tvochess
Hey SG,
i was looking for mates with one single piece-type, but with as many essential pieces as possible. Your rook set-up is good, but I think the queen set-up could be like a bishop set-up with maximum 5 essential pieces.
[fen] 8/1k6/8/8/8/5B1B/7B/5BB1 [/fen]
I'm not sure the position can be reached legally..
Your pawn set-up made me realize ...[text shortened]... iously an illegal position by the way, because there are only 8 white pawns in a regular game.
This position is legal - white's last move was Bd1-f3# or some such. Before that, bK wandered along the long diagonal while the other Bishops took their places.
In your 2nd diagram, we can replace a pawn with a King to make it legal.
- Joined
- 08 Apr 09
- Moves
- 20190
Originally posted by SwissGambitHey SG,
[fen] 8/1k6/8/8/8/5B1B/7B/K4BB1 [/fen]
This position is legal - white's last move was Bd1-f3# or some such. Before that, bK wandered along the long diagonal while the other Bishops took their places.
In your 2nd diagram, we can replace a pawn with a King to make it legal.
[fen]8/2K5/8/4kPP1/2P2PP1/2P2PP1/8/8 b - - 0 1[/fen]
adding the king helps, but there is another problem: the mating pawn move couldn't have occured, because the square it came from is occupied by another pawn. So at least the f4-pawn has to be replaced by a d4-pawn. Then, the last move was d3-d4# (or d2-d4# ).
Number of legal essential 9-piece checkmate patterns with only king and pawns (relative to defending king square) = 4*1*2*2 = 16
Starting from the original 9-pawn mate set-up:
- the king should replace 1 of the 4 pawns covering the corner squares. Replacing other pawns makes other pawns redundant or is illegal. So the king could be on c7, g7, c3 or g3.
- the c and g pawns (or replaced by a king) are fixed. These cover d and f files, which if covered with e-pawns would lead to redundancy.
- there are 2 possibilities for the mating pawn (covering e5), i.e. d4 and f4 --> this dictates the position of the pawn covering e4 (so 2 combinations d4+f3 and d3+f4)
- there are 2 independent possibilites for the pawn covering e6 (d5+f5)
I'm just wasting time.