Is it normal to fart in public in Japan?
Depends.It depends
An accidental fart can happen anywhere, including in Japan. Deliberately making a scene with it is generally considered impolite, much like in many places.
Bodies don’t follow travel etiquette, so an unexpected fart in public is just an awkward human moment. In Japan, as elsewhere, people generally try to be discreet and considerate in shared spaces.
If it happens, a quiet “excuse me” or simply moving on is usually enough. Intentionally letting one rip for attention may get you some disapproving looks—but that’s not a uniquely Japanese rule.