Makunouchi-bento is a type of bento (lunch box) with white rice and several accompanying dishes. As the word "Makunouchi-bento" has a history of several hundred years, there are various theories as to its detailed definition and features.
The history of bento themselves is long, and if a bento is defined as meals to go, its origin is not known. Records show that there was such a practice in Japan in the fifth century at the latest. The origin of bento with white rice and accompanying dishes is not clear, either.
It is considered to be the mid Edo period that people started to call the bento consisting of white rice and accompanying dishes, which is more well-prepared than just rice balls, 'Makunouchi-bento.'
It was around this time that the original form of Japanese-style restaurants was established and they started to prepare and sell bento. They targeted audiences who came to see theatrical plays as well and their bento were provided to the places for entertaining guests such as tea houses called Shibai jaya which were located inside theaters.
The bento were eaten during the intermission, makuai or makunouchi in Japanese, which resulted in the name 'Makunouchi-bento.'
There are other explanations for the origin of the name: one is that makunouchi means 'behind curtains,' describing where actors ate their bento. Another is that as Komusubi (a sumo wrestler of the fourth highest rank) is one of Makunouchi-rikishi (wrestlers in the senior division), people came to call the bento with small rice balls (which can be called Komusubi in Japanese) Makunouchi-bento. There is an opposing theory that as sumo-jaya (sumo teahouse) served similar kinds of bento to the sumo audiences, the word "makunouchi" was brought to the world of sumo such as Makunouchi-rikishi, but objections exist to this theory, too. Containers such as tiered food boxes were frequently used to serve Makunouchi-bento, but also used were disposable boxes made of paper-thin sheets of wood like the ones of the present time.
After the Meiji period, Makunouchi-bento spread as one style of ekiben (a bento sold on a train or at a station). Being sold as an ekiben meant that containers could not be collected, which contributed to the rapid spread of using disposable paper-thin wood boxes. However, as a Makunouchi-bento was the typical and standard type of bento, people did not always call it 'Makunouchi-bento,' but just called it bento or obento, a boxed lunch. In the late 20th century, ekiben tended to feature local specialties as well as specific ingredients but Makunouchi-bento remain popular. Now bento are available at convenience stores and Makunouchi-bento make up a certain part of the section. Makunouchi-bento, although inconspicuous, continue to be appreciated as the mainstream of the boxed lunch.
Generally, white rice is used. There are different opinions on whether to categorize bento with takikomi-gohan (rice cooked with other ingredients) or maze-gohan (cooked rice with added ingredients) as Makunouchi-bento. A traditional Makunouchi-bento has barrel-shaped rice balls sprinkled with sesame (mainly black sesame) lining inside the box. The reason for this is probably because it started with rice balls. Recently, Makunouchi-bento with real rice balls are rarities, as they usually have white rice embossed with a barrel-like shape and sometimes sprinkled with black sesame, dried seaweed or tsukudani (small fish, shellfish, konbu, etc. boiled in sweetened soy sauce) and so on.
Makunouchi-bento usually have a varied assortment of accompanying dishes, which do not contain much moisture, each in a small amount. In particular, broiled fish, a Japanese style omelet, kamaboko or fish sausage (the above together are sometimes called the three sacred imperial treasures of Makunouchi-bento), deep-fried food, Japanese pickles and boiled and seasoned food can be seen in many Makunouchi-bento as they are the typical accompanying dishes of Makunouchi-bento. Those with a hamburger, an omelet or sausage are often called Western style Makunouchi-bento. Some bento feature local specialties or luxurious food as accompanying dishes and are often named after these featuring dishes, but in reality, they can often be categorized as Makunouchi-bento.
Shokado-bento have a similar style with a combination of white rice and accompanying dishes. However, a Shokado-bento is a newer style bento which was developed in the early Showa period. Their origins are very much different: while the Makunouchi-bento was developed from Honzen ryori (full-course haute cuisine), the Shokado-bento arose out of Kaiseki ryori (tea-ceremony dishes).
However, there has lately been some confusion over the difference with people calling a Makunouchi-bento in a box with cross-shaped partitions 'Shokado-bento.'