What's the longest checkmate a chess program has ever found?

I know there exists something like tablebases for up to 7 pieces. So I know it's easy for chess software to discover a checkmate in +100 moves.

But what about positions which would not lead to the usage of tablebases when given to chess software to solve?

I also know there do exist chess puzzles with very long solutions. Like Otto Blathy's monster of 290 moves.

But what about other positions? For example, has your computer ever found a mate in 30 with 20 pieces on the board? Or did you ever find one?

I'm wondering how long a checkmate would be found.

Cheers.

Thanks, it's an interesting story. I do think that the chess program must have relied on tablebases though, would it not? I strongly assume that the program could evaluate this position to endgame databases. And that's why it could proclaim a mate in 196. But what about positions in which a program cannot reduce the position to positions in tablebases?

Perhaps it wasn't such an interesting question to have asked...

I think you should retitle your topic as Longest Mating Combination

Glad you like the idea. It's hard to answer though.

Don't know how to change the title.

Komodo said to me, "Maté in 800 minutes, I'm thirsty." I said to Komodo: "You can't drink, you'll have an attack." And Komodo said:"Mind your own business."

That was a funny ending.

If you review Pre-Capablanca games, Im sure someone miss a mate in 30, 35, 40 move combination.

Ellen Gilbert did once announce a mate in 35 in a correspondence game. And she must have done it without endgame databases as it was 1879 back then. I don't know if her mate in 35 is actually correct though.

http://www.chessgames.com/perl/chessgame?gid=1283517

Can anyone or any program do better without the usage of endgame databases?