In Tokyo's upscale Ginza district where consumers shop for their handbags and smartphones, furious farmers drove their tractors down the main street last week to protest Japan joining the Trans-Pacific Partnership free-trade pact.

The stunt was an illustration of the way the country's agricultural forces are pushing up against modern glitz. As Japan nears a self-imposed deadline to decide whether to participate in negotiations on the TPP, it must first resolve a clash between farmers who think the pact will ruin them and exporters who want to access new markets with lower tariffs.

Nine other countries, including the United States, have committed to the agreement, which would eliminate tariffs and trade barriers in all member nations within 10 years. In Japan, though, the prospect of across-the-board trade liberalization has raised fundamental questions about the nation's shrinking economy, and whether the business or agricultural sector needs the most help.