The longest checkmate problem - 290 move

well yours is impossible to solve but blatny's is possible because the idea here is very simple ;)

Go for it, dude. Let us know how it turns out.

The same engines that solve the starting position you mean ?

Had a postion mate in 2 the engines can't crack it :$ 

Either the mate in 2 is not there, or you entered the position incorrectly (for instance, "forgetting" to mention possible en passant captures...)

https://www.youtube.com/watch?v=7p0Hyry-8bk

( The longest mate which was ever composed is my mate in 552 moves

- have a look at youtube , the link above )

...

yes you're right

Wasn't there a puzzle that went for over 500 moves once? 

Yes , it is my worldrecord-mate for longest legal mate-composition from 2020 in 555 moves :

https://www.youtube.com/watch?v=98LjJL5Awd8&ab_channel=LutzNeweklowsky

cheers Lutz

My worldrecord with mate in 555 moves has a C+ from my friend in Kobe ( he used FUGAKU )

cheers Lutz

Here is a win in 400 moves

I wonder how long the game would have been to reach such a terrible position. Respect for one who created it.

i included this puzzle in my post! 

https://www.chess.com/blog/MrCheesec4ke/so-hardd-insanely-difficult-chess-puzzles

Even though mate in 290 may seem very difficult and impossible, it is actually pretty easy to figure out

So far as I know this position posted by myself is the longest published mate at 1098 ply (549 full moves).

The widely published White to play position after 1...BxQ is mate in 1097 ply (548.5 full moves).

(Not yet spotted my name in the Guiness book though.)

The current record by Lutz Neweklowsky is on 555 white moves, 1109 plies. The number of plies for your construction is a miscalculation and should be 1098!

Never was very good at arithmetic.

Fixed it.