The Heianjō inlay school (Heianjō zōgan) represents a lineage of Kyōto-based tōsōgu makers whose work descended directly from the Onin tsuba tradition. Flourishing from the late Muromachi period through the Edo period, these artisans produced exclusively unsigned works, making their precise workshop organization and individual makers difficult to identify. The school's name derives from Heianjō, the classical name for Kyōto, reflecting their capital origins and courtly aesthetic sensibilities. Chronologically, the earliest Heianjō works stood quite close to Onin tsuba, sharing both temporal proximity and technical foundations with that formative tradition.

The collective style of Heianjō inlay evolved through distinct technical phases. Early works employed brass suemon-zōgan (flush inlay) to develop ornamental, pattern-like designs, often incorporating small openwork (ko-sukashi) and the distinctive "shadow" openwork (kage-sukashi) near tang apertures. The school favored maru-gata (round) and nadekaku-gata (rounded-square) forms with generous proportions and substantial mass, typically finished with tsuchime-ji (hammered ground) surfaces and okezoko-mimi ("bucket-bottom" rim) construction. As the tradition matured, the palette expanded beyond brass to include gold, silver, suaka (refined copper), shakudō, and yamagane used in combination, while pictorial designs were introduced alongside traditional karakusa (scrolling vine) and geometric patterns. Some examples mixed suemon-zōgan with hira-zōgan (flat inlay) and incorporated sukidashi-bori takabori (raised carving in scooped-out relief), demonstrating progressive technical sophistication.

The Heianjō school established a significant lineage within Kyōto metalwork, from which emerged both derivative traditions and named workshops. Koike Yoshiro founded a separate line, while groups signing as Nagayoshi, Yoshinaga, and Masashige developed related approaches. The school's characteristic combination of forceful inlay work with refined openwork techniques and elegant, courtly design sensibilities made their tsuba distinctive. Works said to have been handed down in prestigious warrior families, such as the Uesugi, attest to the school's reputation among the highest military elite during the Momoyama and early Edo periods.