[citation needed] It is most likely that the British introduced the spice mix called curry powder to Japan[3] via the countries respective navies.

[3] The word curry was probably adopted into the Japanese language as karē in the late 1860s, when Japan was forced to abandon its isolation (sakoku) and came into contact with the British Empire.

The oldest Japanese mention of a dish called raisu karē (literally 'rice curry')—but as the misspelt taisu karē—is in cookbooks from 1872.

However, the word was popularized by American professor William S. Clark who was employed at the Sapporo Agricultural College (now Hokkaido University) in 1877.

[8][9] For 1873, there was a dish called curry rice on the menu of the Imperial Japanese Army Military Academy.

[10] During the Meiji era (1868–1912), curry was still perceived in the private sector as a luxury cuisine for the wealthy, available only in high-end yōshoku specialty restaurants.

Curry became a food that could be stored for long periods of time and, like instant noodles, could be eaten in three minutes with boiling water.

[18][19] Since detailed technical information on the retort pouch, which was a military technology, was not publicly available, Otsuka Foods Company developed it in cooperation with a Group company that developed intravenous drugs using high-temperature sterilization technology.

It was introduced to Japan by Rash Behari Bose (1886–1945) when he began to sell curry at Nakamura-ya [ja], a bakery in Tokyo.

[23] Adding potatoes to curry sauce was introduced by William S. Clark due to rice shortages at the time.

As of 2007, curry sauce is the largest single category of vacuum-sealed foods in Japan, making up over 30% of sales.

Japanese short-grain rice, which is sticky and round, is preferred, rather than the medium-grain variety used in Indian dishes.

[37] It is hypothesized that curry became popular in Japan because the Imperial Japanese Navy, modeled after the British Navy, adopted it as a menu item for its ship's mess,[38] or because it was on the menu of the Imperial Japanese Army's mess hall.

[21] On the other hand, Naoshi Takamori, a naval culinary researcher and former Maritime Self-Defense Force officer, points out that although Japanese military manuals from the 1880s include instructions for making curry, curry did not become common in the Imperial Japanese Navy until the 1920s, during the Showa era.

[38] kaigun karē ('navy curry') of beef or chicken meat, potatoes, onions, carrots, rice and curry roux and a chutney of pickled vegetables (tsukemono) as described in the 1888 cookbook Kaigun kappōjitsu (海軍割烹術, 'Navy Cooking Methods').

The Maritime Self-Defense Force took over this tradition after the war and serves it every Friday with a salad,[39][40][41] with each ship having its own variant.

[citation needed] Japanese curry was introduced to North Korea by Zainichi Koreans who migrated from Japan during the 1960s–1970s repatriation project.

[43] Along with other Japanese cuisine, it was traded by new arrivals for local products and used to bribe Workers' Party cadres.