Tokyo stocks closed at a four-month low Wednesday as investors sold blue chips to avoid risk amid growing worries that Greece may leave the euro zone. The Nikkei Stock Average finished at 8,556.60, down 172.69 points, or 1.98%. The benchmark index sank to its lowest level since Jan. 18, when it closed at 8,550.58, according to (Nikkei) website. The Bank of Japan's decision not to take additional easing measures at its two-day policy board meeting sent the yen higher and increased selling pressure for automakers, electronics makers and other exporters.