Complex sentence: The main office is in Ark Hills in Akasaka, Minato, Tokyo and the branch or representative offices are located in Osaka, Nagoya, Beijing, Ho Chi Minh City, Hanoi, and Singapore.
Split into simpler sentences: The main office is in Ark Hills in Akasaka, Minato, Tokyo. The firm has branch or representative offices in Osaka, Nagoya, Beijing, Ho Chi Minh City, Hanoi, and Singapore.