Serieshelpmate in 11

Black plays 11 moves in a row, and white then mates in one move. Black cannot give check to white on any move other than its last one.

Not that hard but nice geometry!

You did it?

Some good problems are hard, others are easy but all are beautiful! Btw, I would have placed the wK on a different square to invite other black promotions but that's a detail.

It's beautiful. Come to dms and we can swap answers

All the pieces are there for a reason

I don't know what dms is. In this time of the year there are many solving contests I don't want to interfere in. I'll post my answer after 1/1/2024.

First time hearing of serieshelpmates.

It's a pretty popular genre - sort of a crossover between orthodox chess (all moves are standard chess moves) and fairy chess (all moves but the last are played as a long series by one side followed by one move of the other side). Seriesmovers are also familiar to game players who often design their plans initially by playing just their own side. When the planned series looks promising they start alternating sides to refine their calculations.

The solutions feel like endgames moves and often end in perfect (model) checkmate positions.

Btw, there are thousands of not uncommon problem types in the fairy domain. The best composers and solvers tackle many types though most solving contests are still orthodox. Otherwise you only get tiny groups of 2 or 3 solvers for the challenges in their field of expertise.

Yep, this serieshelpmate is posed in a current competition, Advent of Chess, No.14, though they seem to reveal the answer to each problem rather quickly.

as soon as I was done with that puzzle, I came here and posted it.

It's OK to post it after the competition for that puzzle is closed (and tell us that). If you post it earlier there is a real risk that someone will post the answer and someone else reading it might enter it for the competition. This was already tried earlier for the : "selfmate in 4" puzzle in the same competition!

I did not think of others reading this. I thought that I will come here to discuss answers. I will be careful next time to post puzzles only after any competition is over.

That was also the reason I told you to come to personal messages to check answers

You wrote "dms" not "pms". But it appears the competition for this puzzle is now closed so the puzzle can be discussed. Anything you want to discuss about it?

dms are 'direct messages' they're the same thing as private messages.

This is a 12 move variation of the answer. Ignore the white moves

1. Ra2 exd5 2. Rb2 dxe4 3. Ra2 exd3 4. Rb2 dxe2 5. Ra2 e1=B 6. Rb2 Ke6 7. Ra2 Bxd2 8. Rb2 Bxe3 9. Ra2 Bxd4 10. Rb2 Bxe5 11. Ra2 Bc7 12. Rb2 Bd8 13. Re2#

Yes, the author of the composition has designed it that way. In fact, with the king on e6, the black bishop need not go to d8, it could also hide on e.g. e1 after capturing the pawns. This is a professional composition and nothing is by chance. Almost all professional puzzles have a number of "almost solutions" That increases their value. The author also thought a while about "placing the white bishop". It works as well on a1 as it does on h8. In the end he chose for h8 since that makes it less obvious that the pawns on d4 and e5 must go to give the bishop on a1 a function.

The bishop needs to make 2 moves so that it cannot block any check, but those 2 moves can also be utilized to remove the king's escape square. Its beautiful.