I think that's impossible. It might be in the middlegame or endgame, though.
mate in 200?

Unless there's some sort of weird starting position, I don't believe 200 moves could be forced to mate

Unless there's some sort of weird starting position, I don't believe 200 moves could be forced to mate
i agree

There is one with a weird starting position, that's forced mate in something like 269, though I'm not sure about that. It's something like this, though I probably didn't get it exactly right. Tablebases will probably tell you that winning Queen and pawn vs Queen are forced mates in hundreds of moves.
Interesting.
do you think as white with each player every move player the very best moves for their to be a forced mate at the start of the game?