Buffett told Nikkei in an interview that he is "very proud" of the investments that were first disclosed in August 2020, when Berkshire (BRK.B) acquired just over 5% in each company. The increased stakes signal that Buffett is turning his focus back to Japan.

In addition, the 92-year-old said he would consider taking stake in other Japanese companies or partnering with any of the trading houses if they are in need of an investor for a future finance deal.

'We don't think it's impossible that we will partner with them at some point in the future in a specific deal,' he told Nikkei. 'We would love if any of the five would come to us ever and say, 'We're thinking of doing something very big or we're about to buy something and we would like a partner or whatever.''

seekingalpha.com - Warren buffett said to ramp up bets on itochu mitsubishi other japanese trading houses