Nikkei 225 rises 1.3% at morning close, Topix slips 0.02%

The gap between a 1.3% Nikkei gain and a flat-to-lower Topix is the real signal here: strength is concentrated in the blue-chip names that dominate the headline index rather than spread across the broader market. That kind of narrow leadership matters because it can flatter the headline number while the average stock barely moves, and it leaves the market more sensitive to a handful of large constituents. Whether the divergence persists into the next session, or the broader index catches up, is the open question worth watching.