Tokyo's benchmark Nikkei 225 index jumped 1.80 percent to its highest close in almost six years Thursday as a weak yen and record finishes on Wall Street helped propel the market. The headline Nikkei finished up 277.49 points to 15,727.12, its best close since mid-December 2007, while the broader Topix index of all first-section shares added 1.12 percent, or 13.96 points, to 1,261.04.