What's the rarest kind of checkmate?

i said i didnt see actual enpasant chess mates...that I didnt saw it mentioned as rarest match.

DOUBLE DISAMBIGUATED BISHOP CAPTURE MATE

I was playing against Beginner computer and I delivered a pawn discovered checkmate

I delivered a king discovered checkmate to a computer

fool's mate

Doubly disambiguated knight capture checkmate

Bishop and knight checkmate...where both pieces were the result of underpromotion?

Castle mate

oh i have that

this took me way to long to understand.

Has it ever happened? If it's happened more than once (or at all), it's not the rarest.

Instead Of Taking A Pawn As A Checkmate Take A Queen As A Checkmate And Your 3 3 3 Bishops Has The Be The Farthest Square Defend The E5 Square.

1 In 684 Billion. Because Take The Queen. 3 Bishops At The Farthest Square. Defending The E5 Square. Not 1 In 342 Billion.

Can You Get Rarer Than 1 In 684 Billion?

Yes. If a checkmate has been played it's not the rarest. Zero is rarer than one.

As someone else said, we have to define rare first.