Sites of assassinations, murders and suicides; dark, dank tunnels and creepy old abandoned buildings; weird creatures, the stuff of legends whose origins are lost in the mists of time . . . Tokyo harbors dozens -- perhaps even hundreds -- of "ghost spots" where inexplicable, sinister phenomena have reputedly occurred.

Of course many, if not all, of these are likely the harmless manifestations of overactive imaginations. Nonetheless, perhaps we should allow for at least some exceptions.

For one thing, you don't want to mess with Taira no Masakado. A warrior whose exploits are recorded in the historical work "Taiheiki," Masakado led a rebellion against the throne. After being killed in battle in 940, his severed head was sent to Kyoto as a war trophy and hung from a tree for all to see. But what they saw, so the story goes, was the face continuing to grimace and roll its eyes . . . before the head flew back to eastern Japan under its own power.