Buying large shoes in Japan is a bit like trying to find a prime-time TV show that doesn't feature at least one past or present member of AKB48: You know they exist, but it often takes perseverance and a measure of luck to track them down.
Back home in New Zealand I take a perfectly average size 7, but the corresponding Japanese size of 24.5 definitely puts me at the Bigfoot end of the spectrum. Luckily for me, that's still within the standard range, but women over 24.5 and men over 27 (9 in U.S., 8 in U.K.) are "outsize," meaning that a large percentage of the foreign population are going to have problems. And buying shoes online from your favorite store back home can backfire, as the 30-percent import duty on shoes can bump up the total cost considerably.
But it isn't only foreigners in Japan who have a hard time with shoes; younger Japanese are also outgrowing standard sizes. My 15-year-old daughter is of average height but her feet are up to 25 — and still growing — while several of her Japanese girl friends wear 25.5 or 26. Why aren't the retailers taking notice?