Zinc/Aluminum or Stainless Steel Iaito?

Iaito selection: material and training considerations

Searching for an Iaito after receiving permission from your Sensei requires careful consideration. At least, that was my experience when I was allowed to start looking. You must think about the correct length, balance, which sword fits the style you practice, the thickness of the tsuka, what you find aesthetically pleasing and which metal your Iaito is made of. This is closely related to the final weight of the Iaito. This is the aspect I want to explore in more detail. For simplicity, I assume that mounting quality, materials and Ito are of equal quality and focus solely on which material may be most suitable for an Iaito.

In general, you can choose between RVS (stainless steel) or Zinc/Aluminium. Most Iaito produced in Japan are made from Zinc/Aluminium. There are two main reasons for this. The first reason is Japanese legislation. Strict laws regulate sword production, allowing only officially registered swordsmiths to forge Nihonto, with a limit of two swords per month to prevent mass production as seen in China. Zinc/Aluminium Iaito are exempt from these laws. Although China has no such regulations, Chinese forges often choose stainless steel because the know-how for Zinc/Aluminium alloys is limited and large manufacturers are less involved with traditional Japanese sword arts.

The second reason relates to joint and muscle strain. The chosen metal directly affects the weight of the Iaito. Stainless steel and Zinc/Aluminium have very different specific weights, resulting in noticeable differences during training. To build muscles responsibly, it is recommended to gradually increase training weight. Iaido uses relatively isolated muscle groups. Therefore, it is wiser to start training with a Bokken of approximately 500 grams, then progress to an average Iaito weighing between 800 and 1000 grams depending on length, and eventually to a Shinken. Shinken are generally forged from around 950 grams and upward. Following this progression helps prevent injuries such as RSI-related complaints. From this perspective, a Zinc/Aluminium Iaito is the better initial choice.

Difference in weight and density between materials. The main difference between RVS and Zinc/Aluminium lies in specific density. Stainless steel is significantly heavier than Zinc/Aluminium, which has a direct impact on training load.

Material density kg/m3

Aluminium / Zinc 2700 – 3400

Stainless steel 7930

High carbon steel 7800

Aside from joint strain, gradual weight progression also improves technique. If your goal is to train as quickly as possible with an Iaito that closely resembles the weight of a Shinken, a stainless steel Iaito may be more suitable.

Recommended training progression:

Bokken > Zinc/Aluminium Iaito > Shinken

Bokken > Zinc/Aluminium Iaito > Stainless Steel Iaito > Shinken

Bokken > Stainless Steel > Shinken

Many practitioners never transition from Iaito to Shinken, yet the considerations regarding material choice remain the same. Both materials require minimal maintenance and will not rust. Artificial hamon are commonly found on both stainless steel and Zinc/Aluminium Iaito, as neither material undergoes differential hardening.

Japanese craftsmanship and dojo safety

Japan possesses the most advanced knowledge and experience in sword forging. Training with a high-quality Iaito is essential for safe and effective skill development. Safety is a crucial aspect within the dojo. Japanese manufacturers are highly aware of this and subject their Iaito to thorough inspections. This level of attention is not always present in large-scale Chinese production. Japanese sword makers also understand balance, largely determined by blade and handle length, ensuring correct proportions from the forge. All Iaito are equipped with a Bo-Hi to reduce weight. Hanwei Iaito are properly tempered, resulting in strong and durable blades.

As an advisory and sales point, we offer both options. Our range includes stainless steel Iaito from Hanwei and Japanese Zinc/Aluminium Iaito. Be cautious of sellers who strongly promote only one material, as this is often driven by sales motives rather than the buyer’s best interest. Some dojo strongly prefer Iaito made entirely in Japan, in which case consultation with your instructor before purchase is strongly advised.