Clues to a traditionally made blade

[Sevykor]

If you were holding a first-half of the 20th century Japanese sword (Nihonto) in your hands, what clues would need to give way for you to conclude that the blade was made in the traditional manner versus modern methods? A hamon line is present and hardware is respective of traditionally made blades.

[cabowen]

There are several steps to aid in determining if a blade is traditionally made. In some cases, it is necessary however to have in hand experience with ww II era blades to make this determination as some of the differences can be subtle and difficult to impossible to relate through words or photos.

 

Here is one way to check. It starts with the easier determinants and moves to the harder...Notice it does not start with the blade, which is usually the first place one would look:

 

The first thing to look for are any stamps. If there are any seki or showa stamps, the blade is not traditionally made. If it has a star stamp, it should be traditionally made.

 

The next thing to check is the smith himself. If he is a Seki smith, odds are high it is a non-traditionally made blade. If he is listed as a Rikugun Jumei Tosho, odds are high it is a traditionally made blade. Look at the background of the smith. If he has verified lineage, that is, he is known to have been a student of a professional smith, the odds that the blade is traditionally made are increased. Look at the workmanship in the nakago. Is the signature skillfully done, the yasuri-me crisp and even, the lines crisp? Is there a date? All point towards traditionally made but do not guarantee anything.

 

Next, check the blade. Is there a defined pattern to the hada? Are there nie attached to the hada? Are there clearly defined nie in the hamon/habuchi? Are there activities such as sunagashi, kinsuji, ashi, etc.? If yes to all or most of the above, then it is most likely traditionally made. Oil quenched blades are said to be devoid of nie and will have a soft, even, rather featureless nioi-guchi. This is because an oil quench is slower than a water quench and nie are said to not form. Sometimes a traditionally made blade with a suguha hamon will appear to be oil quenched but careful examination should show some nie activity.

 

Sometimes it is difficult to judge the hamon and this is where experience comes in handy....

[Sevykor]

Thank you the very detailed answer. Your help is greatly appreciated. - Richard S.

[drdata]

Humbly adding that the state of polish, or lack of, can play a big role in seeing the hammon and other activities pointed out by Chris.

 

A traditionally made blade could be buffed to a chrome like shine (or worse with a grinding belt as an aid to "sharpening") making it hard to tell what it was. Unfortunately a traditional polish is very expensive. This is where folks may mention getting a window opened, which is to say having a small section of the blade correctly (professionally) polished, so that you can tell what you have and if it worth continued investment.

 

A "wartime" polish, such as seen on a star stamped gendiato, is not be the best as far as making activities clear as they tended to be rushed (done by women) and somewhat shiny/bright (IIRC).

 

Never try and polish a blade yourself if there is any doubt that it may be real/nihonto. More harm will invariably occur.

 

Best regards

[cisco-san]

 

Oil quenched blades are said to be devoid of nie and will have a soft, even, rather featureless nioi-guchi. This is because an oil quench is slower than a water quench and nie are said to not form.

 

Sorry for my ignorance, but why did they not quench all blades in water (and look more like "traditionally made")?!

[paulb]

Klaus,

quenching in water puts considerable stress on a blade and unless well forged the process can damage or even destroy a blade (modern smiths quote a 10% failure rate in quenching).

quenching in oil is more forgiving and puts less stress on the metal. therefore the failure rate is lower and it is possible to differentialy harden blades of lesser quality without introducing fatal faults.

This is an over simplification but is the basic reason for choosing to quench in oil.

[bluboxer]

Another important reason for the oil quench is that the modern steels have higher contents of alloys (manganese,chromium,etc.) along with higher carbon content that increase the ability to harden.They do not have to cool as quickly as a simple steel such as tamahagane to fully harden.

Water is the fastest quench and as Paul explained is the most stressful on the steel.

[Jean]

Quenching in oil gives less brittling steel. Stanley tools when tempered are oil quenched to avoid any accident (hammer sending splinters in the eyes when striking a hard surface)

[cabowen]

Let's be clear here: there is the initial quench which hardens the red hot blade blade and creates the hamon (yaki-ire), and there is tempering which entails heating the blade to a much lower temperature (yaki-modoshi). Tempering reduces the hardness and relieves residual stresses. It may be done in an oil bath at temperature or in a forge then cooled in air or water. The initial quench is traditionally done in water. Mass produced war era blades were often done in oil for the reasons listed above.

[cisco-san]

Many thanks for clarification!