Just tried and got the expected answer :
In chess, looking at your opponent’s pieces is not only allowed but essential to playing the game. Observing the placement and movement of your opponent’s pieces helps you plan your strategy and anticipate their moves. However, if you’re referring to situations like secretly peeking at a hidden plan (in correspondence chess, for example) or breaking rules in a specific chess variant, then it could be considered cheating. But in standard chess, observing your opponent’s pieces is part of fair play.
Could you elaborate on this ?