The Naito pepper, known in Japanese as Naito togarashi, is a variety of chili (Capsicum anuum) from Shinjuku, which is now part of the Tokyo metropolitan area. This pepper, which is mentioned in a 17th-century document by the polymath Hiraga Gennai, became popular during the Edo Period (1603-1868), when it was grown on land belonging to the Naito samurai clan. In the early Edo Period, Naito Shinjuku was an agricultural area, but it became increasingly developed during the 17th and 18th centuries and was the most important shukuba or “post town” (a transportation and trade hub, and stopover for travellers) on the western side of Edo (the old name for Tokyo). During this period of economic growth and prosperity, members of the middle class began to favor white rice over brown rice, due to the former’s softer texture and sweeter flavor. As a consequence of increased white rice consumption, however, large sections of the population began to develop chronic thiamine deficiency, or beriberi, because most of the thiamine (vitamin B1) that occurs naturally in brown rice is removed during the polishing process. In response to this crisis, the ruling Shogunate ordered plots of land to be cultivated around the city to provide the population with fresh vegetables and improve their diet. It was also discovered that people who ate soba noodles made from buckwheat flour were less likely to develop beriberi, and so these noodles and the cultivation of buckwheat became very popular. The preferred seasoning for soba noodles was chili pepper, and the local Naito peppers became an important feature of the regional diet—it is said that the fields of Shinjuku turned red during autumn because of the huge volumes of peppers being grown there.
Naito chilies are small (typically 5-7 centimeters long) and grow upward from the top of the plant in clusters of 8-10 peppers. They are planted in March and April, and the plants start to leaf out substantially in June. The first peppers appear in July, and then mature from green to red in August and September. After October, dried peppers are available. This variety has a richly umami flavor and mild to medium spiciness (usually not more than 20,000 Scoville units) that builds gradually. Naito peppers are used in a variety of ways: In addition to being dried, they may be sliced or shredded and used to season noodles, cheese, sausages, sweets, snacks, and other dishes (including from Mexican, Chinese, Italian, and Mediterranean cuisines); or made into condiments, mixed with miso, vinegar, soy sauce, salt, and oil (yuzu-gosho, for example, is a popular Japanese condiment made from chili paste, yuzu peel, and salt, for which Naito peppers or other varieties can be used). Because of their umami flavor, Naito peppers are also suitable as an ingredient in dashi.
During the late Edo Period, Shinjuku became urbanized and the local population developed a taste for spicier pepper varieties, leading to a decline in the cultivation and consumption of Naito togarashi; by the start of the Meiji era (1868-1912), this variety had almost become extinct. In the early 2000s, a local resident decided to resurrect the Naito pepper, partially in order to encourage urban gardening and food self-sufficiency. By 2010, seeds were recovered from a seed bank and, over the next 3 years, through trial plantings and selection, the variety’s traits were stabilized. Today, Naito peppers are once more being grown throughout Shinjuku, and there is a local project and Slow Food community dedicated to promoting this variety. Seedlings are sold to over 5,000 households each spring, and the project hopes to increase this number to 20,000 (10% of Shinjuku’s households). In addition, local schools have developed a course about Naito togarashi, and students of all ages are growing the peppers in schoolyards or on rooftops, sometimes for use in cooking classes). This represents an excellent initiative to protect local gastronomic heritage while promoting education and food production at the household and community level.