Longest Mate (Official) - Mate in 545

the fifty move rule would have taken place already

You should try reading the history of the 50-move rule. In the past, it had a bunch of exceptions for mate in 60, mate in 70, and so on, but there were just too many exceptions that the exceptions were abolished.

To save us from endgames like these, of course!

A human eye can't even tell white is making progress during the solution. I could make up my own mate in 698 and claim it was a tablebase and no one would question it.

Except it's well documented from the Lomonosov seven man tablebase that this is the longest one.

Like people are going to go research that. :P

I can't tell that white is making progress either. Can this sequence be understood by humans in terms of white slowly achieving certain milestones (e.g., "control square x" or "get king to square y"), or are we stuck just looking at it as a formal exercise?

Perhaps we could learn to recognize the progress, but why would we want to bother?

I watched the sequence all the way through.  Fun to see, but can't learn much from it.  It's amazing that this solution has been worked out, considering the computational difficulty of checking that entire branch of the move tree!  Maybe I'll live long enough for to hear about completion of the 8-man tablebase, but I don't think I'll be around for the 9-man version.

I saw some hanging pieces.  Could you please post all of the subvariations? 

I think it's just amazing  that with tablebases we can find things like this now. I know it's useless, but much of chess' most entertaining aspects are useless.

Question:

Is this definitely the longest mate in the 7 man TB, or just the longest found so far?

Curiosity! I certainly do not expect to use anything I learn here in an actual game.

Im not sure how TB's are made or structured. Is it possible to search for specific things, eg all mates in 23?

Yes, but maybe neither side would want to call the 50-move rule, so the game continues........but, at move 514...Rxd3, black should ask for the 50-move rule draw (now being at a piece disadvantage)....unfortunately, white mates before 50 moves from there....love it !  

Thanx, intersting link. I love that zugzwan position.

It is a capture. The 50-move counter is reset to zero at precisely that move. Black should have claimed draw the move before.

Oh....so don't you have to request the count to begin ?...oh yeah, that makes sense....Remember it happened to me once here in a game. I requested a draw at around 55 moves and got it !....Thanks for the clarity chaotic_iak........  

amazing!

i think this game was very unusual. It might be quite amazing game although it will reach 545 to get a chance to win over a black pieces. Not even today would do its kind of game. Good thing  

Does "complete" mean? I'm just asking because the 6-man Nalimov tablebase at some other site doesn't have endgames with a lone King on one side (I wanted to look at a King and Four Knights against King and it wasn't there).

So, for example, does the Lomonosov have King and Five Knights against King (for completeness and interest regardless of how unlikely it is to ever occur)? 

According to Wikipedia, "By August 2012, tablebases had solved chess for every position with up to seven pieces (the positions with a lone king versus a king and five pieces were omitted because they were considered uninteresting)."So it is almost complete; it's missing the trivial positions (K+5units vs K), but they are uninteresting (either immediate stalemate or the majority side can win easily).