Mates that are difficult for engines

I'd say even FIDE /WFCC could be involved in this by providing a presentation advice for this very common issue.

I do that intentionally to show that the other triangulation works also, it is not wrong if you do it either way at any point where you must do it

understood

it is not wrong... but chess.com says it is

In this mate that I posted earlier on here, whether the king goes to f7 or f8 first to triangulation doesn't matter, as long as each square aling the route can't be checked by a black knight.

Yes, but not by engine evaluation; only because the poster instructed it to do so (lacking a better alternative). One of the primary upgrades for the puzzle engine would have to let a chess engine co-evaluate with the puzzle poster. "Engine-approved" puzzles might be entered by the poster initially but corrected/completed by the engine when required. Wait for that feature to appear on chess.com within the next 10 years. After everyone else has implemented it

LOL!, a very realistic idea of how the Bureaucracy at chess.com works. One would think this was a government controlled entity.

Here is another triangulation/zugzwang mate, it's a mate in 99:

Just for consistancy I made the triangulation one way only when there are actually 2 ways to triangulate...if you do the triangulation the other way you are NOT wrong.

nice, the triangulation zugzwang is that long not because the opponent covers the squares directly so its unobvious why that long path is needed

but i noticed that in one of the times the king didnt go the way to h8/h7, whys that?

because that would have lengthened the mate. Black played 25...e5 instead of moving the Bishop to b8 on that move. I appended the pgn in the original post to show what would happen if Black plays 25...Bb8 instead of 25...e5, basically it allows White to capture the g7 pawn which gives Black less pawn moves to delay the mate.

Hmmm, whatever you are talking about, unless that was meant to be a private message to someone, or perhaps you posted to the wrong thread?

That's why I am still mostly single-tasking on computing devices. Keeps me from entering text in the wrong screens

Looks like they restored my thread here. Here's one that I posted earlier in this thread, but I found an even quicker solution to it...the one that was actually intended (this happens to me sometimes when I'm trying to solve these by myself, and of course I don't have the solution readily available), I had it as a mate in 37, but it is actually a mate in 23, and it is VERY difficult for engines, it has a couple of nice underpromotions:

Congrats on getting your thread back! I've seen that happen before - occasionally. Chess.com actually has an active busy bee support team making and breaking functionality all the time. What's missing is a public bug/change/repair log keeping us informed of all the things happening. Well, that's how it is.

Thanks @Arisktotle, now I can go back to tormenting engines .

a public log of changes, for a closed source website?

really?

Public here obviously refers to common authorized chess.com members, not to the whole world and not exclusively to its own staff. And nobody is interested in the technical stuff, just the chess related functionality and decently rephrased to make sense to the public.

yes, but a full log of changes is not really done in a closed source

e.g. no one knows EXACTLY how caps works, just a rough idea

definitely feature announcements, but not minute stuff like that (which is not technical, it is kinda important to know how caps exactly works)

You make a simple thing complicated. A change log is an umbrella concept which pertains to many different types of change reports. One of them can be especially maintained to keep the public informed of what is being done in the system which affects them. It's not really optional. Probably all providers are obliged by law to inform their customers when they make changes in their services - but I'm not much into those laws. I prefer approaching subjects by reason.

And perhaps I need to add that such a log should be available under a button on your screen after you log on. It's not somewhere in a strange, shielded place in the OS core.