"Son" is mentioned twice in the article with no reference to who that is. Masayoshi Son is the man standing on the left in the photo. According to Wikipedia [1] he is founder and CEO of SoftBank.
http://www.financialexpress.com/industry/how-softbanks-masay...
[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).
https://www.bloomberg.com/billionaires/profiles/tadashi-yana...
After that is Takemitsu Takizaki, of Keyence:
https://www.bloomberg.com/billionaires/profiles/takemitsu-ta...
Bloomberg did a piece on him last year on the Decrypted podcast.
https://www.bloomberg.com/news/audio/2017-05-30/masayoshi-so...