If you have practiced Kendo for a somewhat extended period, it is likely that you have heard of the Four Sicknesses - or Shikai (四戒). These are four things that we should, of course, avoid - which is usually easier said than done - however, the importance of them is not just their avoidance, but study of the sicknesses gives us insights into our own path to improvement.
Through reflection on our own interactions, we can assess how the Shikai played a role in our strikes, or strikes that were made against us. For example, if we are hit with a fantastic Men strike, we can assess the situation that led up to the strike - and we can do this in depth using the context of Shikai.
So, what are they? Well, in short they are: Surprise, Fear, Doubt and Confusion.
To break it down into more depth, I would like to once again make reference to the ‘Kendo Written Exam Example Questions and Example Answers - Shodan to Godan’ (剣道学科審査の問題例と解答例（初段～五段）) , published by the All Japan Kendo Federation.
In the example questions and answers for 4th Dan and 5th Dan candidates, the concept of Shikai is covered in reasonable depth. Here’s what it says:
“Surprise, Fear, Doubt, and Confusion are states of being that we must take care to prepare ourselves against.
- Surprise (Kyou / 驚) You become surprised by circumstances that you are not expecting, so much so that the movements of your mind and body become disturbed. You become unable to make correct judgements, or take relevant measures. You assume a state of being at a loss for what to do.
- Fear (Ku / 懼) You become afraid of your opponent, and your sprit arrives at a standstill. Your limbs begin to tremble, and you lose the ability to move freely.
- Doubt (Gi / 疑) You begin to question the movements of your opponent, you lose the ability to make calm judgements, and you become indecisive.
- Confusion (Waku /惑) You are filled with hesitation, doubt and indecision. In this situation, it is impossible for you to make fast decisions, or swift movements.”
Of course, it is much easier to talk about, or even recognize these ailments, than it is to prevent or avoid them. But through rigid training, experience, and constant reflection, we can reduce the occurrences of them. With a good understanding of Shikai, we can consider how this not only affects our own Kendo, but how it affects the mind of the opponent. We can begin to ask, how are my movements affecting the mental state of my opponent? How can I apply Seme in order to plant the seeds of Shikai in their mind?
The concepts of Shikai, Seme and Datotsu no Kikai are closely interlinked, and none of them really occur independently.
I hope you enjoyed this article, and gives you a chance to contemplate how the Four Sicknesses impact Kendo overall.