In chess, if you say checkmate and your opponent isn't checkmated

In chess, if you say checkmate and your opponent isn't checkmated, do you lose? - Quora

With 5D Chess, you can checkmate in multiple dimensions

Lesson 3 – How to checkmate your opponent's king –

Spent 5 minutes trying to figure out why this wasn't checkmate. Never figured it out and resigned. Another 10 minutes on the analysis screen and I figured it out. : r/chess

It's the Implications We Fear — What Jay Thinks

Took 2 days to realize why this isn't a checkmate (opponent resigned bc they were also confused) : r/AnarchyChess

Chess Dr Eric Silverman

How to Checkmate in 3 Moves in Chess: 7 Steps (with Pictures)

Can a Pawn Take a King in Chess? - EnthuZiastic

Lesson 3 – How to checkmate your opponent's king –

DRAW - Why?? - Chess Forums

8 Special Rules in Chess You Need To Know - The School Of Rook

Check, Checkmate, & Stalemate Differences Explained (with GIFs)

Check, Checkmate, & Stalemate Differences Explained (with GIFs)