Why so many Kurai?

“There are four seasons in Tenshinryu’s Kurai.”

These are the words of Ishii Seizo (石井清造) Sensei, the 8th Shike of Tenshinryu Hyoho. The Keikoba (稽古場, Dojo) is protected from wind, rain, and sunlight by walls and ceilings, and its floors (wooden floors and tatami mats) are even and flat. But outdoors, exposed to wind, rain, and sunlight, the ground is uneven and often hobbled by stones, roots, and grass, and there are slopes. If it’s raining, the ground will be muddy, and if it’s a forest, there will be tree branches overhead. Also, in a real battle, there is not always one enemy. Even indoors, it is rare to find a large space where you can wield a sword to your heart’s content. Low ceilings, duckboards, sliding doors, and walls in hallways and tatami rooms can all restrict and block your movement. Japanese houses and hallways have low ceilings, duckboards, sliding doors, and walls, all of which can restrict and hinder your movement. Because of this, Ishii Sensei also teaches the following:

“Dojo training is blocked by walls. There is no end to the wilderness.”

Practicing only in a wide, stable area will always limit your progress when you consider actual combat. And the movements that are considered in the dojo often deviate from those in actual combat. The idea is that by thinking about actual combat and sometimes practicing outdoors, you can learn a lot of practical lessons. The reason why there are so many Kurai in Tenshinryu is that we assume all kinds of weather and situations. By using multiple Kurai, you can improve your mind, technique, and body from multiple angles. It also reduces the risk of encountering unpredictable enemy stances (Kamae) in actual combat. As discussed earlier, in a real battle, everything needs to be optimized in terms of weather and other conditions. In addition, practicing only a few types of Kurai and movements (techniques) will lead to unbalanced abilities. A multifaceted practice is essential to develop a mind, body, and spirit (心技体 Shin, Gi, Tai) that can respond to any situation. And since ancient times, the unknown has been the most frightening aspect of actual warfare.

“If you know your enemy and know yourself, in a hundred battles you will never be defeated.”
知彼知己者百戦不殆
(from Sun Tzu’s The Art of War)

In other words, “if you don’t know what kind of Kurai your enemy uses and are not familiar with how to use your own Kurai, you will not win at all.”

By learning many types of Kurai, even if the enemy uses a rare type of Kamae, you can find out the strengths and weaknesses from the similarities, if not exactly the same, and take countermeasures.
(For more information, please read the section on “Aigane-no-Kurai 相鐘の位”.) Since ancient times, the claim that techniques and Kamae (Kurai) do not require many types has existed and has been debated at length. However, in a real battle, it is not always possible to decide where to fight at one’s convenience. Of course, you can’t control the weather, either. It is difficult to learn the harshness of such a reality through matches and practice alone, and it is also difficult to understand the true usefulness of having many Kurai. It is also not so easy to receive the right instruction and practice deeply enough to actually demonstrate its usefulness. We must value and learn the weight and significance of the teachings that were nurtured by the premise of killing each other in the past.