TOKYO -- More than 50% of households in Japan's capital will be occupied by only one person in a little over 25 years, according to national estimates of the household makeup of Japan in 2050 by prefecture released earlier this month.

The information unveiled by the National Institute of Population and Social Security Research (IPSS) on Nov. 12 includes a prefecture by prefecture breakdown of household numbers. The ratio of single-person households is expected to climb in all prefectures and hit 54.1% in metropolitan Tokyo. This figure will be more than 40% for 26 other prefectures, or over half of the country's 47 prefectures.

The IPSS estimates are produced every five years based on national census. The main reasons given for the demographic changes are the movement of young people into major cities, and the aging of the population along with low marriage and birth rates.

The total number of households in Japan is expected to be 52.61 million in 2050, down by 5.6% from 2020's 55.71 million. Household numbers will decline in 40 prefectures, including a massive 29.1% drop in Akita and a more than 20% fall in eight other prefectures including Aomori, Iwate, Yamagata Nagasaki, Kochi and Tokushima.

Meanwhile, the number of single-person households is rising, and will go from 21.15 million in 2020 to 23.30 million in 2050. This figure will rise in 32 prefectures, particularly in Okinawa, Saitama, Shiga and Chiba, where the ratio of such households will grow by more than 20%.

The percentage of all households represented by single-person homes will be 44.3% nationally on average, topping 45% in the prefectures of Tokyo, Osaka, Kyoto, Fukuoka, Hokkaido, Kanagawa and Kagoshima.

Additionally, the average number of household members will drop below two in a majority of prefectures by 2040. As of 2020 only Tokyo's average household membership was that low, but by 2040 there will be 26 such prefectures and 34 in 2050. The lowest averages will be Tokyo and Hokkaido's 1.78, while the highest will be Yamagata's 2.15.

With the aging of Japanese society, the number of single households of individuals aged 65 or older will increase in all prefectures. In 2020, the national figure was 7.38 million, and this will jump by 46.9% to 10.84 million by 2050. These households will go from being 13.2% to 20.6% of the total over the same period, and over 20% in 32 prefectures including Ehime at 24.9%, Tokushima at 25.3% and Kochi at 27%.

Multi-person households led by an elderly person will also increase, with such "advanced age households" representing over 50% in 21 prefectures by mid-century. Aside from Tokyo, in every prefecture such households will be over 40% of the total.

Households comprised of a person aged 75 or older will also become more common across all prefectures, doubling or more within Okinawa, Shiga, Saitama and Ibaraki prefectures compared to 2020.

(Japanese original by Shunsuke Kamiashi, Lifestyle, Science & Environment News Department)