Shopping for vegetables in Japan can be rather confusing, even if you get past the initial language barrier. For instance, why are green bell peppers called "pīman," and red or yellow ones "papurika?" And then there are the many type of chili peppers, which are known collectively as tōgarashi.
There's a reason for this, though: The different names are clues as to when each type of pepper was introduced to Japan. Hot and sweet peppers are both members of the capsicum family, and originally came from South and Central America. While there are various theories as to when they were introduced to Japan, an early 19th-century document states that the Portuguese first brought chili peppers to Japan in the mid-16th century. Originally chili peppers were called nanban koshō, which literally means "peppercorns from southern foreign lands." This was eventually superseded by the current name of tōgarashi — karashi (mustard) from China (Tang).
Initially, the spicy little peppers were not eaten. Instead, their seeds were used to grow decorative plants, or the peppers themselves were inserted into tabi (traditional nonstretchy socks or foot coverings) to keep the toes warm.