How do they greet each other when they already know each other in japan?

In Japan, when people who already know each other greet one another, they typically bow as a sign of respect. The depth of the bow can vary depending on the relationship and the context, with a slight bow being common among friends or peers. Additionally, they may say "Konnichiwa" (こんにちは) for "hello" or use more informal greetings depending on their familiarity. Handshakes can also occur, especially in business settings or with foreigners.