Photo/Illutration Paper wrapping of the "shumai" bento shows "70" to mark the anniversary of the box lunch. (Provided by Kiyoken Co.)

YOKOHAMA—Japan on April 10 marked Ekiben Day, celebrating the bento box lunches sold at train stations around the nation.

An association of businesses that sell food products at Japan Railway train stations came up with the idea for Ekiben Day in 1993 on the grounds the kanji for “ben” looks like a combination of the number 4 (April) and the character for 10.

The Japan Anniversary Association in January officially recognized April 10 as Ekiben Day.

The most popular ekiben is undoubtedly Yokohama-based Kiyoken Co.’s “shumai” bento, which marks its 70th anniversary this year.

According to company officials, about 27,000 shumai bento are sold every day.

Kiyoken has close ties to Yokohama Station. In 1908, a former manager of the station and others founded the company after gaining approval to do business within the station.

Kiyoken officials hit upon the shumai idea due in large part to the proximity of Chinatown.

Sales of the shumai bento began in 1954, and the recipe used is the same one that led to the original Chinese dumplings in 1928.

The shumai bento is publicized as being tasty even after it becomes cold. Dried scallops mixed into the minced pork filling of the shumai apparently add a flavor that remains even after the shumai cools off.

The wooden package of the bento box also soaks up excess liquid, thus ensuring that the rice does not become too sticky after it cools. The rice is also steamed in a secret way to maintain proper texture.

The paper wrapping around the bento now has a “70” for the anniversary year.

But there are other items in the illustration on the wrapping that show some of the highlights of Yokohama, such as the Cosmoworld amusement park and Yokohama Bay Bridge.

Akane Yamamoto of Kiyoken’s public relations and marketing department said the company was seeking to make shumai bento a popular local brand.

“Ekiben is a memorable part of a trip that can only be enjoyed while one is traveling to that area,” she said. “We will not open up outlets around the nation.”