Sanshoku, the word for "encroachment" in Japanese, is written with characters meaning "silkworm" and "to eat." Imagine a mulberry leaf, being slowly consumed from the outer edges, nibble by nibble, by writhing white worms. Then overlay this leaf on a map of the Japanese archipelago, and look at the spots where the worms are chewing away: Takeshima off the coast of Shimane Prefecture, which South Korea claims as Dokdo; the Senkaku Islands in Okinawa Prefecture, which Taiwan and China claim as the Diaoyutai; and the islands referred to as the Northern Territories between Hokkaido and Sakhalin, which, after the dissolution of the Soviet Union — which occupied them in 1945 — have remained under control of Russia.
Japan's method for dealing with the disputed territories has been to stand its ground on historical claims, although in Takeshima's case it has proposed arbitration by the International Court of Justice.
These neighboring countries are equally convinced the islands belong to them, and are moving in men and materiel. If they appear to be doing this with impunity, it is because they are fully aware of Japan's ingrained disinclination to resort to armed force. (The sinking of a speedboat of unknown nationality, believed to be on a spy mission from North Korea, by Japan's Coast Guard near Amami Oshima in December 2001 was a rare exception.)