Women accounted for 81 percent of the record 6,409 people reaching their centennial this year, the Health Ministry reported. About 83 percent of the 11,346 Japanese age 100 or older are women, it said.
Among the centenarian set are Kiichi Yagoshi, 101, and his wife, Hatsu, who turns 100 this year. They have been married for 81 years.
The key to a long and fruitful life, according to Kiichi, who neither drinks nor smokes, is "not to overexert yourself, and to live freely."
The average life expectancy in Japan is 84 years for women and 77 years for men, making the Japanese the longest-living population in the world, according to the ministry's National Institute of Population and Social Security. The Japanese have held that honor since 1986. In the United States, on average, women live to age 79 and men live to 73.
The Health Ministry report on centenarians is released each year before a Sept. 15 national holiday, "Respect for the Aged Day."
Prime Minister Keizo Obuchi will send personalized letters and a silver cup to each person turning 100 this year. Premiers have followed this tradition since 1963, but may be forced to give it up because of the sheer number of old people.
Japanese tend to live long because of a relatively healthy diet, said Shigeo Takahashi, head of the institute's department of population dynamics research.
Cancer is the No. 1 killer in Japan, followed by stroke and heart disease. Takahashi said a high salt intake has been a problem in the past, but is declining, pushing up life expectancy.