If you go to a *real* Japanese restaurant often enough, by which I mean somewhere other than the average place in America which only serves sushi, tempura, and teriyaki, or if you happen to have the privilege of regular access to some Japanese home cooking, you will find that something the Japanese call "pumpkin" keeps showing up in all sorts of dishes. But when you finally set eyes on one of these "Japanese pumpkins," you will find that it actually looks nothing like an American pumpkin of the type used to make jack-o-lanterns on Halloween, instead being a dull, dark green in color on the outside, much smaller in size, and much denser than the American pumpkin. This squash, which is called kabocha in Japan, is the best squash I have ever tasted.
Kabocha is the sweetest of all the squashes, even sweeter than the butternut squash, but it is not a sickening, saccharine kind of over-sweetness, but rather a warm, pleasing, soft sweetness, mixed in with a very hearty squash flavor, and an extremely satsifying texture. Kabocha is the only squash I know of where you can just steam it completely plain and eat it straight without even any salt and it will taste so delicious you won't miss a thing.
Not surprisingly, then, kabocha is one of the most beloved foods among the Japanese, who literally do everything with it, steaming it straight-up, boiling it into delectable kabocha soup, breading and frying it, and baking it into candies and pies.
The kabocha may be part of the secret of the good health and long lifespans of the Japanese, as it is loaded with vitamins, including beta carotine, iron, potassium, Vitamin C, folic acid, calcium, and B vitamins. Other advantages of the kabocha as a food source include the fact that that it is available all year round, and that it can be stored for months unrefrigerated without losing any of its flavor.
The tragedy of the kabocha, however, is that this wonderful squash largely remains a secret outside of Japan. Although the vast majority of kabocha are actually grown outside Japan, in places like Australia, New Zealand, California, and Chile, 85 percent of the worldwide kabocha crop is exported to the Japanese market, with only a tiny smattering of kabocha sold in other countries, as a specialty food, and even those often being the small, runty kabocha deemed unfit for Japanese consumption.
The irony of all this, of course, is that the kabocha is not native to Japan. There are actually two types of kabocha, which look and taste quite similar. First there is a slightly smaller, bumpier, slightly less sweet kabocha the Japanese call "Japanese kabocha" which was originally brought to Japan in the 16th century from its native Cambodia by Portuguese sailors (indeed, the word "kabocha" actually comes from a mangled Japanese abbreviation of the Portuguese Cambodia abóbora, meaning "Cambodian squash").
And then there is the brighter green, less bumpy, slightly sweeter kabocha, which the Japanese call "Western Kabocha". This kabocha was actually invented only about 25 years ago when some enterprising California farmers realized that if they bred buttercup squash to look a bit more like and taste a bit more like a weird bumpy squash in Japan, they could make a killing selling the new breed on the Japanese market. Today this "Western Kabocha", sometimes also called "Chestnut Kabocha" because the Japanese feel it tastes a bit like chestnuts, has actually become the most popular version of kabocha, and is the one more commonly found in Japanese supermarkets.