[6][7] Being Japan's answer to McDonald's,[5] it is the second-largest fast-food franchise in Japan after McDonald's, and owns numerous overseas outlets over East Asia, Southeast Asia and Oceania, including China, Taiwan, Hong Kong, South Korea, Singapore, Thailand, Indonesia and the Philippines.

[9] As of February 2014 the publicly traded company runs 1,730 MOS Burger and several AEN, Chef's V and Green Grill stores.

[5][10] Despite the backronym being coined by its founder Satoshi Sakurada, no one was able to explain whether mountains, oceans or suns have to do with burgers.

the company began to use playful English phrases in point-of-purchase marketing materials to explain the name, including "MOSt delicious burger", before it finally settled on the current backronym.

[better source needed][12] Wanting to strike out on his own after returning to Japan he decided to adapt the cook-to-order hamburger concept used by Original Tommy's.

[5] MOS Burger planned to open 500 more outlets in Asia, with 30 in Hong Kong, 250 in South Korea and the rest in Singapore and Taiwan.

A joint venture with Yaohan International and a Chinese firm, it planned to open 3,000 outlets by the end of the year.

[16] In April 2011, MOS Burger opened its first store at Sunnybank Plaza, in Brisbane, Queensland, Australia.