The touch-move rule is simple but is subject to abuse and misunderstanding. Most complaints and inappropriate implementations stem from confusion between deliberate toching and accidental. In youth chess tournaments, especially, players will call the touch-move rule on their opponent after an accidental bump of one piece while reaching for another. Short arms do not always navigate regulation chess boards easily.
The USCF Rule is simple:
“[except when adjusting pieces in their squares after saying ‘I adjust’ (Rule 10A)]… a player on move who deliberately touches one or more pieces, in a manner that may reasonably be interpreted as the
beginning of a move, must move or capture the first piece touched that can be moved or captured.”
USCF Rule 10B
Accidental touches are covered as well:
“A director who believes a player touched a piece by accident should not require the player to move that piece.”In international competition and many countries, FIDE laws apply. The FIDE rules (Article 4) also employ the term "deliberately".
USCF Rule 10E