Prime Minister Shinzo Abe has been vowing for years to take on the vested interests impeding his country's economy. Until now, he hasn't done much to make good on those promises. But he was recently handed a perfect opportunity to do just that.

Japan's 3.3 million rice growers, who together comprise only 2.5 percent of the population, now seem to be the biggest obstacle preventing Japan from completing one of history's biggest trade deals, the U.S.-led Trans-Pacific Partnership. By agreeing to cut Japan's tariffs on rice, Abe could save the TPP deal — and show the country's other powerful economic interests that he means business.

Why is the rice lobby so powerful? It's a combination of history, culture and patronage. An island nation poor in natural resources, Japan has long been obsessed with self-sufficiency, particularly when it comes to food. Rice isn't just the country's staple grain — it's an emotional symbol of nationalism; for millennia, Japanese have been taught that their cherished short-grain rice is the envy of the rest of the world. It's no coincidence that the Japanese word for rice, gohan, also means meal.