What Does "J'adoube" Mean?
In over-the-board chess, there is a critical rule: if you touch a piece, you must move it. But what if you just want to straighten a piece on its square? You say "j'adoube" (French for "I adjust"), and the touch-move rule is suspended for that adjustment.
The touch-move rule
In official chess, the touch-move rule states: if you deliberately touch one of your own pieces, you must move it (if a legal move exists). If you touch an opponent's piece, you must capture it (if a legal capture exists). This rule prevents players from testing moves or positions by handling pieces.
When to say j'adoube
Say "j'adoube" (or "I adjust") before touching the piece. It must be said clearly and audibly. You then have the right to adjust the piece on its square without being forced to move it. You may NOT use j'adoube as a loophole to touch pieces and explore options. It is strictly for physical adjustment.
What if you forget?
If you touch a piece without saying j'adoube, your opponent can invoke the touch-move rule. The arbiter will require you to move the touched piece. This has happened at the highest levels of chess, including World Championship matches.
Pronunciation
J'adoube is pronounced "zhah-DOOB". It is universally understood in chess, regardless of language. You may also say "I adjust" or the equivalent in your language, but "j'adoube" is the traditional and most widely recognised form.