Japanese government bonds rose in early Tokyo trading as investors positioned ahead of the Finance Ministry's auction of about 700 billion yen in 20-year securities. The superlong sector has shown resilience even when investors are reluctant to take on duration risk, with auction performance remaining solid, according to Citi Research's Tomohisa Fujiki.

Fujiki noted that declining net supply and flattened rate hike expectations have supported the market. The yield curve has flattened as investors anticipate fewer interest rate increases, making longer-dated bonds more attractive. The 20-year sale is expected to be digested smoothly, reflecting continued demand for Japanese government debt.

In the broader market, the five-year JGB yield fell 0.5 basis points to 1.865%. The auction comes amid ongoing concerns about Japan's fiscal position and the Bank of Japan's monetary policy trajectory. Investors are closely watching how the auction performs, as it could signal broader sentiment toward Japan's debt issuance strategy.