Japan is on track to register its lowest number of births since records began in 1899, underscoring how sharply demographic reality has diverged from official planning assumptions. 

Based on preliminary data from the first 10 months of 2025, demographers expect total births to fall below 670,000, a level the government had not projected until 2041. 

This would place the milestone 16 years earlier than forecast, eroding the credibility of medium- and low-variant population scenarios used in fiscal and economic planning.

The estimates contrast starkly with projections last updated in 2023 by the National Institute of Population and Social Security Research, which anticipated 749,000 births in 2025 under its central scenario. 

Even the most pessimistic “low variant” forecast had assumed around 681,000 births this year. A sub-670,000 outcome would therefore breach all official planning bands simultaneously.

The scale of the decline presents a direct challenge for Prime Minister Sanae Takaichi, who in late November 2025 convened the first meeting of the Population Strategy Headquarters, a task force she labeled essential to addressing Japan’s “biggest problem.” 

The government allocated roughly $23 billion in 2024 for a three-year program aimed at boosting births and marriage rates.

Yet structural indicators continue to move in the opposite direction. 

Annual marriages, a key variable in a society where births outside marriage remain rare, have fallen below 500,000, about half the 1972 peak. 

At the same time, annual deaths continue to rise. Japan’s population shrank by just over 900,000 people in 2024, compounding pressure on pension systems, taxation, and labor supply.

Masakazu Yamauchi of Waseda University estimates that 2025 births will represent a 3 percent decline from 686,000 recorded in 2024, marking the 10th consecutive year of record-low births. 

The expected figures exclude children born to foreign residents, further highlighting the contraction of Japan’s native population at a time when resistance to immigration is rising.

Economists and opposition politicians have urged authorities to revise their assumptions. 

But doing so would carry political and fiscal consequences. 

“Years of government efforts to raise the birth rate have proven futile,” said Masatoshi Kikuchi of Mizuho Securities, warning that acknowledging the trend would make “higher taxes and lower pension benefits inevitable.”

Some demographers have also examined whether 2026, a hinouma or “fire horse” year in the Japanese astrological calendar, could further distort birth trends. 

In 1966, the last such year, births fell by 25 percent before rebounding in 1967. However, Takashi Inoue of Aoyama Gakuin University dismissed its relevance today, noting that younger generations regard it as historical trivia. 

“I don’t think it will have much of an impact on their marriage or childbirth behaviour,” he said.

The data suggest that Japan’s demographic trajectory is no longer fluctuating around forecasts but settling consistently below them, forcing policymakers to confront limits on social engineering in the face of entrenched economic and social change.