Inherited a Japanese Sword? What to Do (and What NOT to Do)

It usually starts the same way: a sword comes out of a closet, an attic, or a grandfather's gun cabinet. Nobody in the family knows much about it beyond "it came back with grandfather." The first instinct is to clean it up and find out what it's worth. Resist both instincts — in that order.

The most common inherited Japanese sword in the United States is a World War II bring-back. Officers in the Imperial Japanese Army and Navy were expected to carry swords, and many carried family heirlooms or quality-commissioned pieces rather than mass-produced military blades. That means the sword in your hands could be anything from a factory-made military blade to a centuries-old heirloom. The difference is worth thousands of dollars — and the wrong cleaning job can destroy it.

Step one: look at the blade, not the mounts

A sword in military mounts — a brown leather-wrapped handle, metal guard, brown lacquered scabbard — tells you about the period of use, not the blade's origin. The mounts are the uniform; the blade is the person.

Carefully slide the blade out and look at the tang (nakago), the part normally hidden inside the handle. A hand-carved signature, a dark natural patina, and visible file marks all suggest a traditionally made blade. A bright, machine-finished tang with stamped markings points the other way: toward a Showato, a World War II military-production blade made with industrial steel and industrial methods. Showato are historically significant as military artifacts, but they are not considered genuine nihonto under Japanese law, cannot be registered in Japan, and are not eligible for NBTHK certification. They have collector value as military history — just not the same value as a traditionally forged blade.

What NOT to do

Don't polish it. The single most expensive mistake heirs make is "cleaning up" a blade with metal polish, sandpaper, or a buffing wheel. Traditional Japanese polish is a specialized craft; an amateur polish removes the temper line, the grain, and a large share of the value in one afternoon. Rust spots and old oil are problems for a specialist, not a weekend project.

Don't oil it heavily. A light coat of proper sword oil is fine if the blade is dry. Drowning it in WD-40 or gun oil is not. And never touch the polished blade surface with bare fingers — skin oils are acidic and will etch fingerprints into the steel over time.

Don't sell it to the first offer. Pawn shops and general antique dealers routinely undervalue Japanese swords because they can't read them. A blade dismissed as a "$200 wall-hanger" might be a papered antique. Get an informed opinion before any price is discussed.

What TO do

Photograph everything. Blade (both sides), tang, signature if any, mounts, scabbard, and any paperwork, tags, or capture documents that came with it. Good photos are what appraisers and forums need to help you.

Handle it by the tang and the scabbard. Keep fingers off the polished steel. If you must draw it, hold the scabbard in one hand and the handle in the other, and put it back promptly.

Get a real appraisal. A specialist in Japanese swords — not a general militaria dealer — can tell you whether you have a Showato, a genuine nihonto, or something in between, and whether authentication (NBTHK or NTHK papers) is worth pursuing. Authentication costs money and takes time, but for a blade that might be genuine, it is the step that turns a guess into a documented value.

Decide what it is to you. Some inherited swords are family history first and assets second. There is nothing wrong with keeping a Showato as a grandfather's war souvenir, displayed respectfully, and never selling it. Just make that decision with information, not in ignorance.

The bottom line

An inherited Japanese sword is a question, not a windfall — and the way you treat it in the first week decides whether that question ever gets a good answer. Don't clean it, don't sell it, photograph it, and get a specialist's eyes on it. The sword waited seventy years. It can wait one more month for the right appraisal.

SamuraiSwordMan publishes full specs — steel, hardness, and heat treatment — on every blade. If a listing anywhere won't do that, walk away.