Japan's Nikkei Stock Average tumbled on Monday, weighted down by US growth data amid Chinese central bank's decision to maintain existing reserve requirement. Nikkei 225 Index lost 0.66% or 57.88 points and closed at 8,783.34, driven by industrials on the downside. Toyota Motor Corp declined 1.7%, Mazda Motor Corp. dropped 3% and Fujitsu Ltd. gave up 3.4%. Advantest Corp. jumped 12.4 after increasing its annual dividend. Sony Corp, which is US export dependent, fell 1.8%, as Yen kept appreciating against the greenback.