Nikkei 225 falls 3.6%, Topix drops 2.5% at morning close

The size of the gap between the Nikkei and Topix is the detail worth noting: a 3.6% drop against 2.5% points to the same kind of concentration risk that has made Japanese equities so sensitive to a narrow set of large-cap names, meaning the headline index overstates how uniformly the market is being sold. That distinction matters for anyone reading the move as a verdict on Japan broadly rather than on its biggest constituents. Whether the two measures converge or diverge further in the next session is the open question.