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What’s the Science Behind Kuji Kiri (aka. Ninja Hand Signs)?

What's the Science behind Kuji Kiri (aka. Ninja Hand Signs)?

Forming symbols with his hands, the ninja mutters some words. In an instant, he becomes calm but eerily alert.

This ritual of hand signs is kuji (aka. Kuji-kiri and Kuji-in). And the ninja used it to invoke supernatural powers when in danger.

These powers include:

  • Predicting danger
  • Hearing another person’s thoughts
  • Healing injuries
  • Invisibility

Now, all that sounds like superstitious mumbo jumbo. So, is there any science to back this up?

We’ll find out today.

Brief Background about Ninja Hand Signs

The origins of kuji-kiri is hotly debated, with some experts believing it’s from China or India.

Nonetheless, once inside Japan, Tendai Buddhism, Shugendo and Shintoism influenced the practice. They were likely the sources of ninja hand signs.

What is Kuji-kiri?

First, kuji (九字) means nine symbols, and kiri (切) refers to the cutting motion. The nine symbols are: rin, pyo, to, sha, kai, jin, retsu, zai and zen.

Each symbol has a specific meaning. So, to invoke a specific ability, you have to perform the correct symbol.

For example, if a ninja gets injured, he’d perform the kuji symbol for healing (while in a meditative state).

In other words, kuji-kiri is like a meditative prayer. This combination of hand signs, breath, and visualization induces a powerful mental state.

So, does kuji-kiri really give supernatural powers?

No. There is no proof of people gaining extraordinary senses or healing powers.

What kuji does is to trigger a specific mental state for a shinobi. This optimal state of mind helps him function well under stress. And may create ideal conditions for his body to recover a tad faster.

For example, the power to foresee danger is just the intuition of an experienced warrior. Kuji-kiri simply triggers an alert state of awareness, to make that intuition sharper.

What does science say about Kuji-Kiri?

What is the Science behind Kuji Kiri (aka. Ninja Magic)?

Thus far, there’s only one study on kuji-kiri. But, we can refer to studies on practices (like meditation and yoga) for a better understanding. After all, they are all similar.

So, on to the science…

Mie University Study of Kuji-Kiri

The one study on kuji-kiri was by Mie University (School of Medicine). It observed 15 ninja professionals (people experienced with kuji-kiri) in their experiments.

This two part study was also featured at the Miraikan’s “The Ninja: Who Were They?” exhibition.

Kuji-Kiri Study (Part 1)

Kuji kiri Miraikan Conclusion
Credit: Image via en.rocketnews24.com

In the first experiment, the study compared changes in brainwaves and heartbeat (before and after kuji-kiri).

Here’s what they found:

  • Alpha-2 brainwaves increased (indicating heightened yet relaxed awareness). The effect lasted between 3 to 30 minutes.
  • Beta waves (associated with annoyance and anxiety) decreased.
  • Theta waves (connected to deep relaxation or sleep) decreased. It remained that way for roughly 10 minutes.

Kuji-Kiri Study (Part 2)

Experiment 2 - Ninja Kuji Kiri Miraikan
Credit: Image via en.rocketnews24.com

The next experiment compared the fight-or-flight response of participants (before and after kuji-kiri).

Within moments of doing ninja hand signs, the participants experienced:

  • Heightened levels of alpha-2 waves
  • Beta waves dropped, decreasing the effect of stress immediately.

Kuji Kiri Study Conclusion

Kuji-kiri keeps the mind calm, while still maintaining alertness. The near instantaneous effect it has makes it useful in fight-or-flight situations.

This sheds light on why the ninja used it so extensively. And makes it worthwhile for martial artists and self-defense instructors to master.

Interestingly, the brainwave results are similar in studies about meditation. The one advantage kuji-kiri has is its speed of getting you into a calm state of mind.

But, of course, only someone competent in kuji-kiri can change their mental state quickly. Familiarity with each hand sign and loads of meditative practice makes a difference.

So, kuji kiri has observable physiological effects on a person. Anything more than that, like outright invisibility or mind-reading is bullshit.

Let’s take a look at practices that are similar to kuji…

Ancient & Modern Practices like Kuji Kiri

There are many ancient and modern practices that work the same way as kuji-kiri. All of them enable you to change your state of mind.

Meditation

Meditation is like kuji-kiri, without the dynamic hand gestures.

It puts you in a state of deep relaxation, while still keeping you alert. Some forms of meditations can even boost your ability to deal with stimuli.

Science has confirmed this effect with ECG (electrocardiographic) measures, GSR (galvanic skin response) and brain scans.

Unlike meditation, kuji-kiri produces the effect in an instant.

Yet, kuji-kiri is still a form of meditation. In the early stages, you meditate to associate each gesture with a powerful mental state. With enough experience, all you need is a few hand signs to trigger a specific meditative state.

That’s likely why the ninja favoured kuji when in danger. Changing their state of mind swiftly would have been essential for survival.

Yoga (Mudras)

The use of hand gestures is not unique to kuji-kiri. 

In fact, yoga has a set of hand gestures (known as mudras). It also uses asanas (poses) and pranayams (breath control).

Doesn’t this sound just like kuji?

When used with CBT (Cognitive Behavior Therapy) techniques, it lowers stress significantly. And helped students feel a sense of well-being (in this study).

Qigong

Qigong

Qigong is a form of movement meditation that produces a relaxed mental state.

It has parallels to kuji-kiri in that the repeated movements trigger an optimal state of mind.

Despite Qigong’s health benefits, it isn’t practical for ninjas to use when on the run.

Self-hypnosis

Self-hypnosis

Hypnosis is often seen as a stage trick.

Yet, some doctors consider it the oldest form of psychotherapy.

After all, with hypnosis, it’s possible to treat pain and anxiety without the use of drugs. Brain imaging even reveals that hypnosis can blog pain signals.

This leads me to believe that kuji-kiri may also have been a form of self-hypnosis.

Anchoring (NLP)

NLP Anchoring to reduce fears and anchor positive states

NLP (Neurolinguistic Programming) is a discipline that helps you change your behavior, by understanding the language of your mind.

In particular, its anchoring technique seems like the modern version of kuji. Anchoring works like this…

The “anchor” is a gesture, touch or sound that triggers a specific mental (or emotional) state. Through repeated hypnosis and visualization, the anchor gets associated with the mental state.

And then when a situation calls for it, the person can trigger the anchor.

MRI Machine
MRI Machine

In 2010, the anchoring technique helped 76% of patients overcome claustrophobia (and anxiety). This enabled them to undergo MRI scans, with usable images.

A radiographer first identified the exact trigger of the patient’s anxiety. He then dismantled the fear associated with that trigger.

Later on, he anchored the positive memories of a patient to a touch on their shoulder. This simultaneous process enabled these patients to reduce their anxiety.

That said, more studies need to be done on NLP to confirm its effectiveness.

Bottomline: Kuji-kiri and other practices

There are parallels among kuji and other practices. And they all seem to rely on proven meditative principles to change a person’s mental state.

This makes meditation useful for modern-day warriors like yourself.

But, for something that’s quick-to-use (when in danger), ninja hand signs and NLP anchoring is the way to go.

You’ll, of course, need load of practice. Good luck!

And, if this isn’t clear enough, kuji kiri won’t give you any supernatural powers…

About Logen Lanka 181 Articles
Logen is a the founder and editor of WayOfNinja.com. Before his shoulder injury, he was actively involved in street calisthenics, Aikido and obstacle course racing. He has also served his 2-years conscription with the Singapore Armed Forces as an Armoured Infantry Trooper.