Negotiations on the issue of the Northern Territories are often called the last post-war settlement. In December 2016, Japan marked its first step on the thorny path. What did they talk about behind closed doors? How did Japan negotiate with Russia, which wouldn't soften its hardline stance? We learned about some of the details from materials we collected for this report. We'll take a look at what was going on behind the scene during the 7 months of secret negotiations.