Osafune Tadamitsu was a leading master of Sue-Bizen, ranked alongside Katsumitsu and Munemitsu among the foremost smiths of the late Muromachi period. Signature compendia record the Tadamitsu lineage from a first generation placed around the Genko era (1321-1324), though no actual works by such an early figure are encountered. Thereafter, several generations bearing the name span the Nanbokucho through late Muromachi periods. Among the smiths signing Tadamitsu are those who appended titles such as Hikobei no Jo, Shuri no Suke, Kurozaemon, and Heiromon no Jo; of these, the Hikobei line is regarded as particularly skillful. Dated examples by the best-known Tadamitsu bear years of Bunmei (1469-1487), Entoku (1489-1492), and Meio (1492-1501), and an inscription records that he forged swords at Ioka-go in Sakushu (Mimasaka Province) in Entoku 2 (1490). Joint works (gassaku) by Hikobei no Jo and Hikozaburo confirm that Tadamitsu was their shared personal name.

Tadamitsu has long enjoyed a reputation as a superior maker of suguha, yet he also excelled in the inherently Bizen-style midareba. His suguha works display a tightly forged ko-itame with fine ji-nie and a bright, clear nioiguchi, tempered in chu-suguha often mixed with small gunome and accompanied by ko-ashi, ko-nie, and fine sunagashi. In his midare manner, the hamon features open, broad-based gunome as its main tone, frequently mixed with choji and ko-notare, with tobiyaki, ashi and yo entering abundantly, and the nioiguchi bright and clear. The forging shows itame-hada mixed with mokume, often with nagare tendencies and areas of hada-dachi, with midare-utsuri standing forth in the finer examples. The blade carvings -- combining bo-hi with soe-hi, superimposed bonji, rendai, and grass-script kurikara -- are notably rich and skillfully executed. His works span katana, wakizashi, tanto in both hira-zukuri and yoroi-doshi styles, and spears, including large omi-yari of old-form construction.

Tadamitsu's katana clearly demonstrate the uchigatana shape distinctive to the Sengoku period, and his spears rank among the finest surviving koto-period examples. Within Sue-Bizen, his output is distinguished by consistently strong nie, a bright nioiguchi, and workmanship that at its best approaches the quality of the earlier Oei-Bizen masters. The combination of orthodox jihada, accomplished tempering in both suguha and midare modes, and richly carved horimono marks Tadamitsu as a smith of the first rank among late Muromachi-period Bizen makers, and his signed and dated works constitute valuable material for the study of Sue-Bizen production.