cover charge; table charge; compulsory appetizer fee
A small fee charged at some Japanese-style pubs (izakaya) for a mandatory appetizer (otoshi) served with the first drink. Not a tip; it is part of the bill.
This izakaya charges a 300-yen cover charge.
The otoshi fee is like a seating charge.
Compound of お通し (otoshi, 'appetizer served with the first drink') + 代 (dai, 'fee'). The term is specific to Japanese dining culture.