In Japan, tipping is not a tradition. Even today, both giving and accepting tips is often frowned upon (especially away from international tourist areas). In fact, perfect service is considered a matter of course in Japan and does not need to be rewarded with money. In tourist centres or larger hotels, good room service can be rewarded with 100 or 200 yen (1 to 2 euros). But: To do this, you have to put the money in an envelope and write name/function on it. It is considered impolite to give money without an envelope. Another nice idea is to reward good service with small gifts and attentions.