The seppa (pronounced SEP-pah) are the small, often overlooked metal washers that sit on either side of the guard. The word points to a spacer or shim, and that humble role is exactly why they decide whether a katana feels solid or cheap in the hand.
What the Seppa Are
A katana’s mounting is a stack, and the seppa are two of its quietest layers. Working from the blade back, you find the habaki collar, then a seppa, then the guard, then a second seppa, then the fuchi at the mouth of the grip. The two oval washers sandwich the guard and take up every fraction of slack between these parts. They are usually copper or brass, thin enough to flex slightly and bite.
Their Role and How to Judge Them
Without seppa, the guard floats and the whole assembly clicks with every movement — the classic rattle of a badly made sword. The seppa do two things: they compress the stack so the mekugi pin pulls everything tight against the tang, and they protect the soft faces of the guard and fuchi from being scarred by metal-on-metal contact. Good seppa are cut to follow the exact oval of the guard’s collar and finished to match it, so they almost disappear. Poor ones are stamped, oversized, or made of a soft mystery metal that crushes flat and lets the rattle creep back. The test is simple: hold the assembled sword vertically and shake it gently — silence is a pass.
Why It Matters to a Buyer
Seppa are the cheapest part of a katana and the most telling. A maker who fits them properly almost certainly fitted the guard, blade collar, and grip properly too — they are a fingerprint of care. A maker who skips or fakes them has likely rushed everything you cannot see. On any battle-ready katana, well-seated seppa are the difference between a sword that absorbs a cut and one that loosens with use. When you compare blades in our katana collection, listen for the rattle first; the full stack is laid out on the anatomy guide.