Rarest Chess Move

About yesterday I stumbled upon a video documenting on what the "rarest" chess move possible is, using data from Lichess.org. Right here is a redirect to the video, but I would like to write a brief summary on the matter, not only as a "revival" post of my own, but also due to the subject being intriguing to me.

So to even begin the topic, we must define what makes a chess move a chess move. Of course, you can use basic chess notation, like e4 or Ne4 or Qa5#. We can also use a "clarification" of sorts where is 2 or more pieces can move to the same tile. For example, if 2 white Knights can move to e5 and they are on the rank, we can sort them based on what file they lay on. Like Nde5 and Nfe5. Likewise, if they are on the same file we use the ranks. Like N3e5 and N7e5. If they are on both, you use both. An example being Nd3e5. Queens, Bishops and Knights are notable pieces who use these in the video. 

Now for the rarest moves. The move that had the least amount of games that was above a 0 was a "Double Disambiguated Bishop Non-capture Checkmate", where clarification for the notations was needed (remember the Nd3e5 example?) for both file and rank, and a bishop was moved where the bishop didn't deliver checkmate, but it was moved so another piece would put it in checkmate, or a discovered move. Out of Lichess' 324,490,585,837 games, only ONE game had it. Did this make it the rarest? No. The "rarest move" was a tie between a Doubly Disambiguated Capture Checkmate and a Doubly Disambiguated Knight Capture Checkmate for a grand total of absolutely none. Fun!

Again, I put a redirect to the video in the beginning, the person describes it in greater detail, and since it probably took a lot of work I don't want to play a game of just spreading his word around. Huge credit to Paralogical on Youtube for the original video, check him out. Anyways, bye bye.

well, hikaru just did the knight one after seeing the exact same video

he also did the Double Disambiguated Bishop capture Checkmate just after

The video says that Chess.com has more data, it would be nice if they collaborated for a follow-up video, and now these moves have been played.

Yeah, it kinda sucks that the site doesn't make this data public, but you could argue privacy? Not sure. BUt it would be neat.

The video said that there was over 1000 moves that never happened so why is the doubly disambiguated bishop non capture checkmate the rarest?

croissant did it

Agree. But if they collaborate, they don't need to make the database public, only the results.

What is even a Doubly disambiguated bishop non capture checkmate or doubly disambiguated knight capture checkmate?

It's pieces of one kind on the same file and on the same rank (obviously you need to have 3 such pieces then, if there were only two then they'd be stacked on top of each other) that can all move to the same square, so when you want to write the move down you need to write the rank (1st disambiguation) and the file (2nd disambiguation), which makes it a doubly disambiguated move.

I'm sure they can work something

https://www.chess.com/analysis/game/pgn/4xeP3dnppn?tab=analysis&move=0

I think it gaves error when you look at this position.

Like when you play b3+ and they play d5 you take en passant. I don't think nobody did anything like that.

The rarest chess move is known as the "Legal Move" or "Légal's Mate," named after the French player S. Légal. This unique move occurs when a player checkmates their opponent with a knight, while simultaneously putting the opponent’s king in check with a different piece. This scenario involves a specific arrangement of pieces and often arises in puzzles rather than actual games. This makes it a fascinating exploration for chess enthusiasts and a testament to the game's complexity.

Have you even seen the video? That mate doesn't come close to being one of the rarest moves.

I think you are missing the point. Watch the video first.
BTW, I still don't see why Chess.com is not taking the opportunity for an awesome follow up. Perhaps a collaboration among chess, math and programming youtubers.

Disambiguated non-capture en pessant promotion to knight checkmate

Types of rarest moves/positions:

• O-O#
• O-O-O#
• exd3#ℹ️
• Three or more pieces can capture a piece, with checkmate, like Qd4xa1#
• King Mate
• Full Army Mate

And also pawn Mate.