BofA rates are an insult. I once had to wire money from my US BofA account to a foreign HSBC account. The "preferential" BofA rates were 15% worse than spot. I just had the money wired as USD to the foreign account. HSBC received it as USD and then I converted them to the foreign currency at a rate closer to spot. The exchange booths at Japanese airports are better than BofA but they are still pretty lousy compared to spot rates. The 7-11 recommendation is a good one. Maybe take a few JPY just in case, and withdraw from the 7-11 ATM at a much better rate.