# R4 | anthropic/claude-haiku-4.5 | run 1

## Prompt

As of the most recent available estimate, what is the population of Japan, and is it increasing or decreasing? Give the figure and year, and cite sources.

## Response

Japan's population stood at **122.93 million as of July 1, 2026** (provisional estimate), and it is **declining** [stat.go.jp](https://www.stat.go.jp/data/jinsui/new.htm). The population decreased by 440,000 people (–0.35%) compared to July 2025 [stat.go.jp](https://www.stat.go.jp/data/jinsui/pdf/202607.pdf).

This represents the continuation of a long-term downward trend. Japan's population has declined for 17 consecutive years since peaking in 2009 [japantimes.co.jp](https://www.japantimes.co.jp/news/2026/07/30/japan/society/japan-population-fall/), and the latest 2025 census showed the most dramatic decline on record, with a 2.5% drop from the 2020 census [japantimes.co.jp](https://www.japantimes.co.jp/news/2026/05/29/japan/japan-population-largest-decline/).

The decline is driven by aging demographics: those aged 65 and older increased to 36.2 million, while the under-15 population fell to 13.35 million [stat.go.jp](https://www.stat.go.jp/data/jinsui/new.htm). Foreign residents, however, grew 12.14% year-over-year to 3.9 million.

What factors do you think are most significant in driving Japan's population decline?
