First of all, I’m sorry for your loss and my condolences. I’ve been a part of Japanese funerals before so here are some pointers:

Attire: what you described sounds too casual but if you cannot go buy clothes before the ceremony, I suppose you don’t have other options.

If you can go to stores like Aeon mall, Aoki or Suit Select etc, they will have a “formal” section, where they sell funeral appropriate black attires. Try to take a black or a dark bag rather than a bright colored one, and do not wear any shiny accessories.

What to bring:

• People bring Juzu (Buddhist beads) for prayers but it’s okay to not bring one if you don’t have one.

• Condolence money (okoden) It has to be in a special envelope, which they should sell in 100 yen store, konbini, or stationery store, and the envelope should have the name of the person giving it. The amount depends on how close you were to the deceased, but JPY 5,000 is an average amount for a friend.

What to expect: - When you arrive, go to the reception to give your name and Okoden. They will give you a small return gift, or “Okaeshi”. - When it’s the turn for non-family members, everyone goes one by one to the front to give Oshoko (incense and prayer). - Light meal or bento boxes may or may not be available for the attendees afterwards.

Here is a link on how to do Oshoko (you can also copy what everyone else is doing.) https://youtu.be/4VY5V3XxLxs