What Is Mekugi-ana? 目釘穴 — Reading a Sword's Peg Holes
The mekugi-ana (目釘穴) is the peg hole drilled through a Japanese sword's tang (nakago) through which the bamboo mekugi passes to lock the blade securely into the handle (tsuka). Every mounted nihonto needs at least one mekugi-ana; the tapered bamboo pin seated in it is the only thing holding an otherwise loose blade inside its hilt. Because the tang and its holes are never re-polished, the mekugi-ana is one of the most honest and information-rich features a collector can read.
To a buyer, the number, position, shape and condition of the peg holes are a compact history of the sword. A single clean hole suggests an untouched blade; extra holes, plugged holes or holes cut through part of a signature immediately raise questions about shortening, remounting and authenticity that directly affect value.
How the mekugi-ana is made and used
The hole is punched or drilled through the widest, flat part of the tang so the mekugi crosses the full thickness of the steel. A traditional bamboo peg (take-mekugi) is preferred over metal because bamboo flexes, grips and warns of failure before it snaps, whereas a rigid metal pin can shear under shock. The peg is fitted slightly tapered and driven from one side so vibration tightens rather than loosens it.
On the tang itself, the placement of the mekugi-ana is deliberate: it sits where the tsuka's core and the tang overlap with enough steel around the hole to resist tearing out during a cut. Reading that placement against the overall tang shape is a routine part of appraisal (kantei).
What extra and altered holes tell you
A blade will often carry more than one mekugi-ana, and each tells a story:
- Single original hole (ubu-ana) — one hole in an unaltered tang points to a blade that has kept its original length and mounting geometry, consistent with an ubu (unshortened) sword.
- Multiple holes — additional holes usually mean the blade was re-handled one or more times, or that the balance point shifted when the sword was shortened, requiring a new hole in a better position.
- Plugged hole (umegane / lead plug) — a hole filled with copper, brass or lead shows a peg position was abandoned, often after shortening changed where the mekugi needed to sit.
- Hole cutting a signature — a mekugi-ana that clips or destroys part of the mei is strong physical evidence of shortening (suriage), because the tang was cut down and a new hole was drilled without regard to the older signature.
Reading holes for shortening and authenticity
Shortening (suriage) removes steel from the base of the tang, so the original mekugi-ana ends up too close to the new tang end to be useful, and a fresh hole is drilled higher up. The result is a lower, partly cut or plugged old hole plus a cleaner new one. A tang whose only hole sits oddly close to the machi, with a second plugged hole below it, is almost always a shortened blade rather than an original short sword.
Authenticity checks lean on the hole too. On a genuinely old tang the edges of the mekugi-ana carry the same deep, even patina (sabi) as the surrounding steel, and any drilling burr is long gone. A bright, sharp-edged hole through a tang claiming to be centuries old, or a signature suspiciously untouched despite a hole placed where shortening should have disturbed it, are classic warning signs of a faked or altered piece.
Why the mekugi-ana matters to a buyer
Condition and originality drive nihonto value, and the peg holes speak to both. An ubu tang with one honest hole and an intact signature commands a premium; a heavily shortened blade with several holes and a truncated mei is still collectible but priced accordingly. Just as important, the mekugi-ana is a safety feature — before handling or displaying a mounted sword, confirm the bamboo peg is sound and fully seated, because a failed mekugi lets the blade fly free of the handle.
Frequently asked questions
Why do some Japanese swords have more than one mekugi-ana?
Extra holes almost always mean the blade was remounted or shortened over its life. Each time the sword was re-handled or cut down, a new peg hole was often drilled to keep the balance and grip correct, leaving the older holes behind as evidence.
Does a mekugi-ana through the signature reduce a sword's value?
A hole that cuts into the mei confirms the blade was shortened (suriage), which usually lowers value compared with an untouched sword of the same maker. That said, many important shortened blades remain highly collectible, and the shortening itself can help authenticate the piece.
Should the mekugi peg be bamboo or metal?
Traditional bamboo (take-mekugi) is strongly preferred because it flexes, grips the hole well, and tends to warn before failing. A rigid metal pin can shear suddenly under the shock of handling, so most collectors keep a properly fitted bamboo peg in place.
Can a bright, clean mekugi-ana indicate a fake?
It can. On a genuinely old tang the hole's edges share the same deep patina as the surrounding steel. A sharp-edged, bright hole on a tang claimed to be centuries old is a red flag that the tang was freshly drilled or artificially aged.