You are able to set up the company a minimum of one yen as a capital, but would you want to do business with a company whose capital is one yen?
Its credibility is doubtful, and it might soon be insolvent so that it is recommended that you have sufficient capital.
To do business in Japan, you should be prepared to invest about 5 million yen capital. This investment can include not only cash but also property, such as real estate, cars and credit.