In which district of Tokyo was this cache hidden?
The answer : Roppongi
The Mission 6: Asian Arms geocache (GCDF3) is the only one of the fourteen Project A.P.E. caches hidden in Asia. This promotional operation by Fox for Tim Burton's Planet of the Apes scattered fourteen boxes around the world in the summer of 2001, each holding a genuine prop from the film; the sixth was placed in Tokyo on 28 June.
Here there was neither forest nor trail. The published coordinates pointed to Roppongi, and the cache page warned that the ordeal would be psychological rather than physical. You had to spot an anonymous building, a door marked with ape symbols, dial the number written on it and wait for a guard to come and take you to the treasure — Monday to Friday only.
A Japanese geocacher, horiken, turned up on 30 June and signed the logbook two days after the cache was placed. He left empty-handed: the main prize, a club used in the film, was on display in Shibuya at the time. He was promised it would be sent to him after the exhibition; in mid-August he wrote that he still had not received it. The second and last to claim it was a foreigner passing through, Troy, of the GeoMonkeys team: with no GPS, he walked the street for three hours before running into another geocacher who had one. Geocaching was virtually non-existent in Japan at the time, and Mission 6 attracted hardly any other visitors before being archived.
The answer : Roppongi