can white force a mate here?

Yes, nice irrelevant link. I am still waiting for an example.

We have 7-man TB, that mate is beyond the TB. Certainly will SF get it by sheer calculation. But that's not the question.

lichess.org/editor/N7/2p4p/5p2/7p/5p2/5p1p/5p2/5K1k w - - 0 1

If forced or not is irrelevant. Nuff said.

I rest my case.

in which game did that happen?

Irrelevant question.

it _is_ the question. If Stockfish can calc it in under 20 ply or if it is in the tablebase then lichess can automatically check after a game if it is mate and then it can grant the win or not.

That would mean that the current solution is not the only workable solution (not that it is perfect. It just randomly declares some positions, simple enough, to be draw).

It is mate in 13. It is neither in the TB nor can it be calculated within 20 plies because it has 25 (or 26) plies. And it should be legal.

Good luck and good bye!

Answer the question.

So, your silence suggests that my claim "In real games (forced mate possible, but it can not be recognized by engine or tablebases) has probably never happened in the history of chess." can not be refuted. Your fear of false detects is therefore more or less unfounded. Nice to have made that clear :-)

Have a nice Saturday.

Sarg0n DID answer your question (and has answered tons of other identical questions). You just don't like the answer.

New rule: you have to demonstrate the helpmate with the time you have left. You don't deserve to win just because you were half a second faster than your opponent if that half second isn't enough for you to mate him even with full control of both armies.