Japan's decision to join the TPP makes sense for two key reasons. First, the current structure of the Japanese economy, especially the agricultural sector, is not sustainable. As Japan's Council to Promote the Revitalisation of Food, Agriculture, Forestry and Fisheries made clear in its October report, these sectors are under severe strain. Problems include declining incomes, shortages of farmers and an aging population. Addressing these issues will require a reorganisation of the country's agricultural sector — whether Japan enters the TPP or not.
Second, Japan's export sector is increasingly suffering from trade diversion, as key trading competitors like South Korea benefit from their various FTAs. For example, the EU-Korea FTA and the EU-US FTA mean that Korean cars will enter the EU and US markets more cheaply than those from Japan. This will make life increasingly difficult for Japanese car manufacturers seeking to export their goods. And while Japan does have a network of economic partnership agreements, most are not with major trading partners.