It’s a question that many Westerners have asked for decades: How did Christmas in Japan become synonymous with fast food? Foreigners may laugh at the lines that form outside branches of KFC on Dec 24, or the people reserving their buckets of chicken a month in advance, but it turns out that they’ve only got themselves to blame. The tradition of eating KFC at Christmas dates back to the early 1970s, when an expat customer at the chain’s Aoyama store observed that, in a land bereft of Yuletide turkey, fried chicken was the next best thing. The store’s canny manager was paying attention and passed word on to the higher-ups, leading the company to launch its ludicrously successful “Kurisumasu ni wa kentakkii!” (Kentucky for Christmas!) campaign in 1974.