How Portuguese "soap" became Japanese "cactus"

A golden barrel cactus, known in Japanese as キンシャチ (kinshachi) or 金鯱 in kanji

As the first Europeans to make contact with the Japanese, the Portuguese contributed a lot of new words to the Japanese language as part of a broader cultural exchange. One very unusual word is: さぼてん (saboten), also written using the Chinese characters 仙人掌 or 覇王樹, which means "cactus".

Now one might immediately protest that cactus is cato in European Portuguese, and cacto in Brazil. How is 'saboten' from the Portuguese?

Well, it turns out that 'saboten' came from the Portuguese word sabão, meaning soap. Over time, the Japanese suffix te (手, meaning hand, helper, or means of action) was attached, and 'sabon-te' became 'saboten'. But what's the connection with soap? One can no longer be completely sure after many hundreds of years, but it appears that the Portuguese were known to use cactus stems (possibly aloe vera) to remove stains. With very few exceptions, cacti are native to the Americas, so these types of succulent were first introduced to Japan by the Portuguese. Ever curious, the Japanese must have marveled at these strange plants and wondered what uses they had.

A related explanation is that the Japanese thought the Portuguese used cacti to make soap (again, most likely aloe vera). The Japanese already had a word for soap, borrowed from the Chinese: 石鹸 (sekken). They added the word シャボン (shabon) from the Portuguese sabão as a synonym. To this day, it is still amusing for the Japanese to learn that their words for soap and cactus have a common root.

The restaurant motif is a stylized golden barrel cactus, called 金鯱 (kinshachi) in Japanese.

Saboten is also the name of a Japanese restaurant chain of 豚カツ (tonkatsu), a delicious form of fried pork cutlet eaten with a special sauce and piles of shredded cabbage. When Mr. and Mrs. Tanuma founded the restaurant in Tokyo in 1966, they were inspired by these hardy plants that could thrive even in the harshest conditions. Today, Saboten restaurants, like their cactus namesake, can be found all across Japan, Korea, Taiwan, Singapore, Thailand, Hong Kong, and even Canada!