HONOLULU -- The incursion of a Chinese nuclear-powered submarine into Japanese territorial waters Nov. 10 has illuminated the mounting competition under the surface of the Pacific and Indian oceans and their adjacent seas.

The chief rivals for submarine supremacy in this region are China, which has put priority on submarines in developing a deep-sea navy, and the United States, which is rebuilding submarine capabilities that had atrophied after the Cold War.

China and the U.S. are not alone. North Korea has a sizable coastal submarine force, and South Korea has begun to counter it. Japan has a modest but proficient fleet. Taiwan is pondering the procurement of eight subs, which would triple the size of its force.