Warren Buffett shocked Tokyo markets last August with a $6 billion (?659 billion) bet on Japan¡¯s five largest trading houses.

One year on, his investments are paying off.

Amid the surge in commodity prices, the collective value of Berkshire Hathaway Inc.¡¯s stakes in the five s¨­g¨­ sh¨­sha has risen by about $2 billion. That gain of more than 30% has outpaced the benchmark Topix index¡¯s 21% rise, and doesn¡¯t account for dividend income.