The Shimosaka school of Echizen Province was a collective enterprise in which several smiths forged blades under the shared trademark "Shimosaka." In the earliest phase, the first-generation Yasutsugu is thought to have served as the group's central figure. Signatures occur in multiple forms -- "Echizen no Kuni Shimosaka," "Higo Daijō Shimosaka," and "Higo Daijō Fujiwara Shimosaka" -- and among those bearing the Higo Daijō title, at least three contemporaneous smiths are identified: Yasutsugu, Sadakuni, and Kanenori. The NBTHK has noted that the chisel movement and brush-like intent in their characters are alike or of the same tendency, and their workmanship styles share common features, making it difficult at present to assign individual Shimosaka signatures to specific hands on a definitive basis.

The school's characteristic mode is a forging of itame-hada mixed with mokume, flowing overall with a tendency toward standing grain (hada-dachi), producing conspicuous shirake-like effects. Ji-nie and chikei are present, and the steel sometimes shows an admixture of somewhat blackish kane. The hamon typically takes the form of a narrow suguha or chū-suguha with a tightening nioiguchi and ko-nie; fine sunagashi are applied, and the nioiguchi tends toward a shizumi (subdued) quality. Where midare elements appear, they manifest as shallow notare mixed with gunome, with ko-ashi entering and hotsure and kinsuji enlivening the habuchi. A further hallmark of the school is the relief carving (ukibori) of "true" kurikara and other subjects executed within hi on both sides -- work displaying the distinctive traits of Kinai-bori (Echizen Kinai-style carving), rendered with powerful chisel finishing.

The Shimosaka school's works span katana, wakizashi, tantō, and naginata, and are consistently recognized as superior pieces within the early shintō tradition. Their blades are valued both as accomplished examples of Echizen craftsmanship and as important reference material for understanding the formative period of the Shimosaka group before individual identities fully crystallized.