With three pawns and a bishop, white will not surprise you with his promotion attempts...until you see it.

Brilliant study by the incredible Troitsky, 1925.

phenomenal! But then, one expects nothing less from Troitsky...

did he set that up or was that in an actual game?

I would say it is a study i.e. 'he set it up' - he is famous for endgame analysis and composition, not so much for competitive chess..

The promotions were bog standard - the mate was excellent.

promotions to a bishop on identically-coloured squares as an existing bishop is *not* quite something one sees everyday :)

But 5T4R5CR34M has a point: if you think about it logically, what else is there? But will the promotions work? Yes, if one can discover that excellent mate.

Hmm - IOW - I completely agree with 5T4R5CR34M - because isn't that what my previous paragraph comes to?

I couldn't say it any better.

It is exellent.

i don't see why a promotion to a knight doesn't work :P ... but hey, that's just me :).

Wow, I was trying to compose a position a few weeks back where the only winning move was a bihop promotion, I spent about 30 mins on it and gave up, this is unbelievable!

cause then Kb7 and a piece is lost

Cause then Kb7 and a piece is lost

Excellent question!

Or

I thought the most amazing promotion would be to promote to a king.  lol  :)  Just kidding.  Very nice puzzle.  :)

Your suggestion demonstrates that you have the makings of an outstanding problemist!

nice puzzle

wow amazing.....

This truly is a really amazing puzzle, one of my favourites.