What is Kenyoku Ho and when should you use it?
September 3, 2026
Kokyū · Breath
The Breath in the Belly, Measured in Tokyo
Fifteen people who had never meditated sat for twenty minutes with their attention on the breath in the lower abdomen. Their brains, their brainwaves, their mood and their blood all changed, and a Japanese physiology department wrote it down.
Jōshin Kokyū Hō, focusing the Mind with the Breath, is a foundation practice within the system of Reiki.
The study
A Zen breathing practice, put under the sensors
In Zen training, attention is placed on the movement of breath in the Tanden, the point a few finger-widths below the navel. In the system of Reiki this same point is the Hara, and breathing into it is the first instruction of Jōshin Kokyū Hō. Researchers at Toho University School of Medicine in Tokyo wanted to know what this does, physiologically, to someone who has never done it before.
Fifteen volunteers sat for a twenty-minute session of focused attention on Tanden breathing. While they did, a 24-channel near-infrared spectroscopy cap measured blood flow across the front of the brain, EEG electrodes recorded brainwave activity, a mood questionnaire was completed before and after, and blood was drawn to measure serotonin.
- Design
- Within-subject, before and after one session
- Participants
- 15 healthy adults, novices
- Measured
- Prefrontal blood flow, EEG, mood, blood serotonin
- Where
- Toho University, Tokyo
What they found
Four things moved in twenty minutes
The front of the brain lit up
Oxygenated haemoglobin in the anterior prefrontal cortex, the region most involved in sustained attention and self-awareness, rose significantly during the breathing. Attention on the belly showed up as activity at the forehead.
Negative mood fell
Compared with before the session, participants reported less negative mood afterwards. One sitting, twenty minutes, people who had never done it before.
Brainwaves settled
EEG showed alpha activity rising and theta activity falling, both during the practice and after it. Alpha is the pattern of relaxed, wakeful attention; the shift persisted once the breathing had stopped.
Serotonin rose in the blood
Whole-blood serotonin increased significantly, and the size of the increase tracked the EEG changes. The authors propose that the prefrontal activation and the serotonin system together account for the improvement in mood.
The researchers were not studying Reiki. They were studying the belly breath of Zen. But the instruction they gave their volunteers is the one you give yourself: attention on the breath, low in the body.
This is Jōshin Kokyū Hō with sensors attached
The practice the Tokyo team studied is, in its bones, the first movement of Jōshin Kokyū Hō: breath drawn down to the Hara and held in attention there. Everything the volunteers were asked to do, a practitioner of the system of Reiki does at the start of every sitting. What the study adds is a picture of what that does inside a person in real time.
Three things are worth holding. The effect was immediate, in novices, in a single session. The changes were in the body, not just in self-report: blood flow, brainwaves, serotonin. And the brain region that activated was the one associated with attention turned inward, which is a reasonable description of what the manual calls purifying the Mindful Heart, Kokoro, with the breath.
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Limitations
A small study with an elegant design and clear limits.
- Fifteen people.Small enough that a handful of unusual responders could shape the averages. The finding needs repeating at scale.
- No control group.Everyone did the same thing. Sitting quietly for twenty minutes doing anything might produce some of these changes. The design cannot separate the breathing from the sitting.
- One session, no follow-up.This shows what happens during and just after. It says nothing about weeks or months of daily practice.
- Serotonin in the blood is not serotonin in the brain.Whole-blood serotonin is mostly held in platelets. Its relationship to mood-related brain serotonin is indirect.
- Novices only.Experienced practitioners may respond differently, possibly more, possibly less. This tells us about beginners.
- Correlation between EEG and serotonin.The two moved together. The study cannot say which drove which, or whether a third factor drove both.
The research
Yu, X., Fumoto, M., Nakatani, Y., Sekiyama, T., Kikuchi, H., Seki, Y., Sato-Suzuki, I., & Arita, H. (2011). Activation of the anterior prefrontal cortex and serotonergic system is associated with improvements in mood and EEG changes induced by Zen meditation practice in novices. International Journal of Psychophysiology, 80(2), 103–111.
This is research into breathing, not into Reiki, Reiki treatments or Reiki training. It is included here because breath is one of the foundation practices of the system.
Breathe into the Hara, below your navel, sometimes called your tanden.
Somewhere behind your forehead, something is already answering.
