In Japan, public displays of affection are generally discouraged and kissing in public is seen as inappropriate. There are no specific laws against it but it could result in stares or even verbal reprimands. If caught engaging in a passionate kiss with someone who isn't your partner or family member, the police may be called and you could face a fine or even jail time depending on the severity of the offense. To express love for someone without breaking any laws or social norms, alternatives such as hugging (if appropriate), holding hands (if appropriate), exchanging small gifts like flowers or candy etc. can be used instead.