This ō-suriage wakizashi was originally signed, though the substantial shortening of the tang has removed the smith's personal name. The remaining inscription reads "Yokoyama Uenosuke Daijō Fujiwara" on one side and "Bizen Osafune" on the other, indicating that the blade was made by a member of the distinguished Yokoyama school of Bizen.
The Yokoyama school carried forward the renowned Osafune tradition during the late Edo period and is particularly celebrated for producing elegant blades with vibrant chōji-midare hamon. Measuring 54.2 cm in length with a graceful curvature of 2.3 cm, this blade retains a magnificent and lively chōji-midare, displaying the flamboyant tempering style for which Bizen swords are famous.
Although the smith's individual name was lost when the blade was shortened, the remaining signature strongly suggests it was originally the work of a Yokoyama Sukesada (祐定), one of the generations who inherited the famous Sukesada name within the Yokoyama lineage.
This sword was officially registered in November 1952 (Shōwa 27) and bears an early four-digit registration number. Early registrations are often referred to by collectors as "Daimyō Registration", as many were submitted by former daimyō families, noble households, and samurai families during the initial registration process. While this was not universally the case, early registration numbers are generally regarded as an indication that a blade came from an established prewar collection, adding an extra layer of historical interest and provenance.
The sword is mounted in Type 98 guntō koshirae with a leather-covered scabbard, typical of field-service mounts. The remounting of traditionally forged blades into military fittings was common during the wartime period, reflecting continued functional use.