[saagarjha]

The Wikipedia page has this interesting piece of trivia about him:

[H]e is the richest man in Japan, despite having the distinction of losing the most money in history (approximately $70bn during the dot com crash of 2000).

[adventured]

By a large margin over Masayoshi Son, the richest in Japan title now goes to Tadashi Yanai of Fast Retailing:

https://www.bloomberg.com/billionaires/profiles/tadashi-yana...

After that is Takemitsu Takizaki, of Keyence:

https://www.bloomberg.com/billionaires/profiles/takemitsu-ta...