Tokyo stocks fell 1.65 percent on Monday morning, continuing the instability in see-sawing world stocks amid worries over the eurozone debt crisis and a slowdown in the global economy. The Nikkei 225 index at the Tokyo Stock Exchange stopped for lunch down 140.90 points at 8,419.36. The benchmark index was briefly down more than two percent to hit the worst intraday low since March 15, just days after the 9.0 earthquake and tsunami hit Japan.