Taking Caution when Discerning Truth and Lies found in War Documents

There are many interesting documents of old that describe all sorts of trades, practices, cultural topics from pre-modern Japan. This is especially true for those who are enthusiasts of Japanese martial/military history, for there are many resources on said topic. Some famous documents are usually easy to obtain as great strides are taken to make these more readily available to the public. Then there are those rare gems that are part of individuals’ personal collection or found in second-hand bookstores, which, if lucky, may be shared either through exclusive meetings, events based on invitations, or even online. While it’s tempting to take all martial/military-related documents at face-value and view them as windows into the past, it’s also important to discern genuine from fabrication.

There is a term for documents that we must be wary about, which is “gisaku” (偽作). While it’s simple to translate this term as “forgery” or “fake”, this term actually has more layers to its use. There are reasons to labeling an old document gisaku, which could range from, but not limited to, the following:

  • A document having reputable information, but is a direct copy (i.e. Chinese war strategies that were copied for use in Japan, but this fact is not stated)
  • A particular family or group claiming genuine tactics, but in reality they were copied & altered to appear “genuine” (i.e. clandestine tactics that were copied from another reputable source, but arranged to fit a specific narrative unique to the individuals in question)
  • A document containing unusual/suspicious practices that may be made up (i.e. ritual practices said to be done before setting out to the battlefield, which in truth seems out of place compared to other historical recordings)
  • Stories & notes in the form of a war journal, which may be exaggerated (i.e. A family journal claiming great exploits in certain events, but unverifiable in legitimate historical records)

In the following text below, certain excerpts from a source entitled, “Buke Kojitsu Gunrei bassho” (武家故実軍令抜書, Excerpts of Customary Practices and Rules of the Samurai) will be used to illustrate this point about war documents that could be labeled as gisaku. Unfortunately, the author of this is not mentioned, which leans it closer to not the most trust-worthy of documents as there’s no way to verify the information.


Before we look at these excerpts, I will explain some background pointers. The topic of this document is a small, sharp implement called a “kōgai” (笄). While normally labeled as a hairpin primarily used by women in the past, there was a similar version synonymous to warriors during the Sengoku Period all the way to mid/late Edo period. The kōgai used by warriors was a key component found inserted into the opening of their sword’s scabbard. Its’ usage varied slightly throughout the ages in Japan, as it went through some alterations from having specific functions to becoming a decorative standard accessory on the scabbard. The kōgai is regarded as one of the “mitokoromono” (三所物), which were 3 essential items that accompanied one’s sword (high-ranking or lower-ranking alike) , which included the menuki (目貫) and kozuka (小柄).

Image of a kōgai. From Kotobank.jp

Take note that a word of caution comes with the contents of this document; while there is evidence regarding the importance of the kōgai and the mitokoromono, it has not been verified that its usage as a multi-purpose tool as mentioned here to be true. It is also highly possible that this was written during Edo period, way after Japan was moving towards an era of peace, being that there may be some romanticizing ideas here at play that glorify things that never was practiced by warriors of old.


Below are seven excerpts from Buke Kojitsu Gunrei bassho. Note that while the title for each excerpt will be translated from Japanese to English, the explanation for each will not be a direct translation, but instead will be more of a description. Also, without being too opinionated, I added a comment below for each one, mainly based on similar practices to each one.

#1: Using a kōgai to insert a head-trophy marker during a battle (軍場の首札としての使い方)
Warriors get rewarded for the number of enemy soldiers they slay on the battlefield. There are several ways of claiming one’s “head-trophy” during battle, which will then be evaluated later. One of the ways is to put a form of marker in their hair. For this document, it is said that for slain enemies who have no hair (such as a warrior monk), to pierce one’s kōgai into their ear to create a hole, in which then a head trophy marker can be inserted.

COMMENT: In my limited research, this is reminiscent of other methods of leaving a marker on a slain opponent that will be used as your prize. This one is unique for bald soldier, which is new to me.

#2: Using a kōgai when your horse is tired while in battle (軍場で馬が疲労した時の使い方)
When riding an exhausted horse on the battlefield, there should be someone, such as a stable boy, to assist with resolving the situation. When found alone and no one to help, you would use your kōgai to pierce into the lower part of its leg to perform phlebotomy.

COMMENT: Since high-ranking warriors were privileged to riding on horseback, attendants tend to be close by to assist in various ways. While some details are missing, this sounds like a method to spur on your horse to be reinvigorated by inflicting pain to it.

#3: When the Commander gives a retainer his kōgai (大将が臣下に笄をお渡しになる場合があること)
In this case, a retainer is used as a spy and sent out by his Commander to handle certain tasks in enemy territory. The commander will give the retainer a specific kōgai, which allows the retainer to be recognized during meetups upon his return.

COMMENT: While this sounds like something from a spy thriller, this is highly possible. Whether or not this method was truly used is a different story.

#4: Using the kōgai to scale a castle wall (塀越の時の使い方)
In the event where a castle wall needs to be scaled, one’s kōgai can be used by inserting it into the gap of the stone foundation. This way, you step on the kōgai to propel you up in order to reach the top of the castle wall. If in a group, the person most skilled at this will perform this task. When there is doubt amongst your group about how to scale the wall, suggest using the kōgai will help for reinsurance.

COMMENT: I’ve heard of steel pegs and the like being inserted into the crevice of a stone wall in order to climb up a castle back during Japan’s warring times. I wouldn’t rule out the effectiveness of a kōgai being used for such a task, although it is a pretty short implement.

#5: Using a kōgai during a night raid (戦場で夜討する時の使い方)
Your group has taken down the enemy’s fort at night, but you do not have time to claim the heads of your slain opponents. In the case where the enemy commander, or any other high-ranking warrior, was slain by your hands, then you should stab your kōgai into the eye or ear of your victim. This way, it can be verified later.

COMMENT: This is possible, as I’ve heard other examples of leaving a form of mark on slain soldiers that can later be identified as being that from a specific individual. It is also said that if the kōgai is part of your mitokoromono that has a unique motif, then there won’t be any dispute as it being yours.

#6: Using kōgai-gakure while at an inn when traveling about (旅の宿における笄隠れ)
When there is a concern about being watched while in your room at an inn, you are advised to make your room dark without actually quenching the flame from the andō (行燈), which is a paper-encased oil lantern. The trick is as followed: pass a wooden skewer stick over the flame in the lamp, while vertically placing you kōgai in front of the flame. Forming a cross formation, the light from the lamp will be blocked, giving the impression that you are going to sleep. This is the method for “kōgai-gakure”.

If your suspicions are correct, and thieves and the like sneak into your room, you can pull your kōgai away to light up the room in an instance, exposing your perpetrators.

COMMENT: Interesting tricks like this can be found in some war documents. While they sound pretty cool, in many cases they are very situational, and tend to be missing additional information.

#7: Using a kōgai as chopsticks (箸に用いる使い方)
When your group has set up camp and are about to eat, you can use your kōgai as chopsticks when proper ones are not available. You can also use the kōgai to skewer pickled items.

COMMENT: While a kōgai was generally a solid, singular metallic object, there was another version where it was 2, detachable pieces, which could then double as chopsticks. However, this 2-piece kōgai was devised, from my understanding, much later during Edo period, so it’s abit skeptical that such a version was made beforehand.


Researching old documentations on martial/military contents can be both fun and informative. However, it’s best to take the information you read with a grain of salt. Some contents are easier to verify than others, while finding unique/obscure documents doesn’t mean you’ve found a treasure trove. At the end of the day, documents like the one mentioned above make for an interesting read that can be further researched on for further verification, but nothing to announce to the world as top secret strategies you’ve miraculously discovered.