Perhaps you've heard, but it's become Christmas tradition in Japan to eat fried chicken--particularly KFC, for dinner. While KFC releases special Christmas buckets and meals every year to fuel the festivities (and now there's a Pepsi specially designed to pair with fried chicken), many in Japan are now surprised to see that their KFC Christmas tradition is being celebrated in another country...by KFC.

While giving a lecture in Spain, contemporary paper cutout artist Yusuke Shimomura (@yuusuke_shimo) stumbled upon an advertisement at their local KFC that advertised a chicken burger that seemed like it was tailor-made for release in Japan: The Otaku Burger!

Shimomura and now the many who were surprised by the viral Tweet immediately recognized the Japanese “お祝い” (“celebration”) and “美味” (“delicious”) written on the screen, as well as red, white, and gold (colors used traditionally to represent good luck during the New Year in Japan), but the name "Otaku Burger", and what could constitute one, struck them the most.

Some further investigation at the KFC Spain website reveals that the new menu items (along with the Otaku Burger are Otaku Buckets an chicken pieces) are part of a promotional "Los Otaku" campaign by KFC Spain to introduce and encourage the Japanese Christmas tradition of KFC dining (the ads for the burger explain that it's customary to eat KFC on Christmas in Japan). Of course, that means giving the burgers and chicken a Japanese twist--Otaku Sauce.

According to the website, the Otaku Burger contains two original chicken fillets, buns, lettuce, mayonnaise, and "Otaku" (teriyaki) sauce. So it seems that the secret ingredient to being an otaku is teriyaki sauce!

KFC Spain further explained on their Twitter account that they released the Otaku Burger because it's tradition to eat KFC in Japan, wanted to slather everything in teriyaki sauce, and because hey, it's cool! They even released a series of commercials where they ask Japanese students, cosplayers, and commuters "Why do Japanese eat KFC for Christmas?" Some of the answers include "because it's fun to gather all together and have it," "it's delicious," and "well, because it's Christmas!"

It's a satisfactory explanation by both KFC and those interviewed. Besides, if you know anything about KFC Spain's Twitter account, you know that they are very otaku-friendly:

You can watch the full commercials below.