Introduction

A saidan-mei (裁断銘) is an inscription found on the nakago (茎, tang) of a Japanese sword (nihontō, 日本刀) that records tameshigiri (試し斬り, test cutting results). These inscriptions document the effectiveness of a blade in cutting through multiple targets, such as human corpses, armor, or bundled straw mats, under controlled conditions.

A sword that successfully passed high-level tameshigiri was considered an exceptional weapon, and the presence of a saidan-mei increased the sword’s historical and monetary value.

This guide explores the purpose, history, types, and notable figures associated with saidan-mei.

Purpose and Importance of Saidan-Mei

1. Authentication of a Sword’s Cutting Ability

  • Saidan-mei provided proof that a blade was tested and performed well.
  • A sword that cut through multiple bodies or tough materials was considered highly valuable.

2. Historical Documentation of Tameshigiri

  • Many daimyō (feudal lords) and samurai commissioned test cutting to ensure their swords were battle-ready.
  • Tameshigiri was often conducted by official executioners (otameshi-geisha, 御試し役), who recorded the results.

3. Prestige and Value Enhancement

  • A sword with a successful cutting test inscribed on its tang increased in value.
  • Certain saidan-mei indicated the sword was capable of extraordinary cuts, making it a status symbol.

Types of Saidan-Mei (裁断銘の種類)

Saidan-mei inscriptions vary depending on what was cut, who conducted the test, and where the cuts were made on the body. Below are the most common types:

1. Number of Bodies Cut (Dō-dan, 胴断)

One of the most well-known tameshigiri tests involved cutting through multiple corpses (usually criminals) stacked on top of each other.

A. Ichi-dō (一胴) – One Body Cut

  • Indicates the sword successfully cut through a single human torso.

B. Ni-dō (二胴) – Two Bodies Cut

  • The blade passed through two stacked bodies, showing superior sharpness and momentum retention.

C. San-dō (三胴) – Three Bodies Cut

  • A high-level test where the sword cut through three human torsos in a single stroke.

D. Shi-dō (四胴) – Four Bodies Cut

  • Extremely rare and required an exceptionally well-forged blade.

E. Go-dō (五胴) – Five Bodies Cut

  • Considered legendary, a sword capable of cutting through five bodies in one strike was regarded as a masterpiece.

2. Cutting Location on the Body (Test Cut Positioning)

Some inscriptions specify where the cut was made on the body.

A. Kesagiri (袈裟斬り) – “Diagonal Cut”

  • A diagonal downward slash from shoulder to opposite hip.
  • Considered one of the most effective cutting techniques.

B. Suemono-giri (据え物斬り) – “Fixed Object Cut”

  • Cutting a stationary body or object, such as a mounted corpse or a bundle of tatami mats.

C. Katate-giri (片手斬り) – “One-Handed Cut”

  • The sword was tested using only one hand, demonstrating blade control and sharpness.

D. Dotan-giri (土壇斬り) – “Executioner’s Cut”

  • A horizontal cut at the waist level, commonly performed on prisoners during execution.

E. Saiha-giri (裁破斬り) – “Armor Cutting Test”

  • The blade was tested against armor or protective gear to assess its battlefield effectiveness.

3. Names of Tameshigiri Testers

Tameshigiri was often performed by highly skilled executioners, and their names were sometimes inscribed alongside the test results.

A. Yamano Ka’emon (山野加右衛門)

  • One of the most famous sword testers of the Edo period.
  • Many swords with saidan-mei bear his name, indicating official testing.

B. Yamano Nagahisa (山野長久)

  • A member of the Yamano family, which specialized in sword testing for the Tokugawa Shogunate.

C. Yamano Kanjūrō (山野勘十郎)

  • Another famous otameshi-geisha known for executing precise tameshigiri tests.