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This helpmate is a little bit more interesting. Helpmate in 2: White is on move.



1. Bxa8 Rxa8 [...Kxa8 extends the helpmate over 2 moves]
2. cxb6#

Originally posted by Uries
This helpmate is a little bit more interesting. Helpmate in 2: White is on move.

[fen]n6r/k1K5/pp6/2P5/8/8/6B1/8 w - - 0 1[/fen]

1. Bxa8 Rxa8 [...Kxa8 extends the helpmate over 2 moves]
2. cxb6#

Unfortunately, this position is not legal - where did the bNa8 come from to deliver check?

Originally posted by Uries
[fen]r7/k1K5/p7/8/4p3/8/P4PP1/8 w - - 0 1[/fen]

Kind of similar to another position posted but extended a bit. Don't think I've seen the promotion idea used yet so here it is.

Helpmate in 4 moves on the condition that black doesn't move his rook or a pawn.

1. f3/f4 exf3(ep)
2. a3 fxg2 [2.a4 forces black to move one of the forbidden pieces]
3. a4 g1=Q
4. a5 Qb6+
5. axb6#

Why not just remove Pf2 and Pg2, and start Pe4 on g4?

Then, instead of adding a condition that Black may not move his R or Pa6, just use a wB and keep it orthodox:



The only remaining flaw is the dual solution 3.g1B 4.Bb6...

Originally posted by SwissGambit
The only remaining flaw is the dual solution 3.g1B 4.Bb6...

And that flaw is easily fixed:


h#4

Now we have a sound, orthodox h#4 with the promotion idea and a neat little side idea thrown in: Pa2 steps slowly so that the timing is correct at the end.

Originally posted by SwissGambit
Unfortunately, this position is not legal - where did the bNa8 come from to deliver check?

Just exchange the night for a rook and then its good. I was wondering the same thing too though.

Originally posted by tomtom232
Just exchange the night for a rook and then its good. I was wondering the same thing too though.

If you put a Rook on a8, White can just play 1.cxb6# right away. Same goes for any other type of piece besides an N or P, which are illegal.

Originally posted by SwissGambit
If you put a Rook on a8, White can just play 1.cxb6# right away. Same goes for any other type of piece besides an N or P, which are illegal.

Oh yeah... Well I just guessed based of the moves given by uries... Still no excuse for my ignorance.

Originally posted by tomtom232
Oh yeah... Well I just guessed based of the moves given by uries... Still no excuse for my ignorance.

Composing helpmates is not as trivial as it may seem at first. Keeping cooks out is more of a challenge in a helpmate, where any legal mate solves, than in a forced mate, where Black can be expected to play good defense.