When a severe rice shortage sent prices skyrocketing in Japan last year, Tokyo restaurant owner Arata Hirano did what had once seemed unthinkable: He switched to an American variety.

The price of the Californian Calrose rice he buys has doubled since his first purchase last summer, but even so, it's far cheaper than homegrown grains.

"Unless domestic prices fall below Calrose prices, I don't plan to switch back," said Hirano, whose restaurant offers meal sets of fish, rice, soup and sides.