The Healing Wisdom in a Cup of Sayu
Woodblock Print, c.1800.
Tuukka Toivonen October 28, 2025
“It means that this ability to improve, to be healthy and happy, is always within us. […] Illness occurs when we don’t live according to the law of nature—when we are in dis-ease with nature.” —Kazuko Hillyer Tatsumura, in Healing Your Healing Power (2020)
Contemporary society has invented a virtually infinite variety of beverages to help keep us hydrated and provide us with refreshment. The mere act of selecting a coffee, tea, soda, smoothie or milk to suit our taste has become a feat of some complexity, requiring special attention. But, in the midst of such abundance, how often do we pay serious attention to the temperature of the drink we choose? Beyond opting for cold drinks in the summer or hot teas and coffees in cooler seasons, how likely are we to think about temperature beyond this crude hot-cold binary? And how attuned are we to sensing which drink temperature might actually feel best and have a beneficial effect on our bodies?
I gave little attention to such subtleties until recently, when I began to notice a strange habit proliferating among my Japanese friends. Instead of unthinkingly accepting the usual offer of cold water with ice while sitting at a Tokyo restaurant, they would insist on being served sayu instead. While the word literally translates as ‘white’ or plain hot water (白湯), what normally arrives is a cup of warm water that is comfortable to drink—neither too hot or tepid.
The standard response to a casual inquiry about a person’s preference for sayu is that it helps one’s body and intestines remain warm. Prodded further, a sayu drinker usually goes on to explain that excessively cooling the insides of one’s body is not only unnecessary and uncomfortable but also harmful to health, especially for women. The slight inconvenience of politely refusing icy drinks therefore seems well worth the effort as it is viewed as a way to ward off disease.¹ For many of my friends it therefore appears to be the natural and obvious thing to do (even if the vast majority of restaurants in Japan do not appreciate this preference just yet!).
When the opportunity arose, a few months back, to join a well-known Japanese holistic summer retreat rooted in East Asian notions of self-healing I began to reflect further on the significance of sayu. I began to see how the simple practice of ingesting warm water might conceal within it an entire system of thought, built around notions of energy, balance, and non-interference in natural processes.
The minimalistic retreat in the foothills of Mt. Ariake—housed in calming wooden buildings carefully embedded in the local terrain—was designed around the three simple pillars of food, rest and light movement. Nurtured by two daily macrobiotic meals, ample sleep and long walks along pristine mountain rivers and forest paths away from urban noise, I proceeded to undergo an unexpected, quiet transformation during my five-day stay. This culminated in a profound sense of lightness, insight and joy and there was a sensation of simultaneous physical and mental healing and wholeness. I found myself leaving the retreat with a greatly strengthened interest in the nature of self-healing.
Soon after returning to my urban life I began to perceive how, my regenerative research interests notwithstanding, I had previously hesitated to fully embrace the total intelligence of my own body, from astonishing intrinsic ability to heal to its tendency to align with myriad rhythms beyond its boundaries. I had not appreciated deeply enough the ways that such intelligence—from subtle bodily sensations to circadian rhythms, the fluctuations of the nervous system and the aliveness of the microbiome—sustain us as living beings and constantly interact with and adapt to the world around us.
“The underlying system of healing views nature’s energy as immensely more powerful and superior to anything that humans might themselves invent or implement.”
Having been through a powerful healing experience in a setting that was distinctly non-interventionist was, therefore, a rather humbling experience. I began to wonder anew whether our conscious rational selves had much to do at all with fundamental healing processes. Perhaps we were no more in charge of the dynamics of our bodily health than we were able to consciously control our billions of gut microbes. Is our equating of self-healing with ‘self-care’ a delusion, owing to a misplaced confidence in the ability of the self to direct and, indeed, lead the healing process? Just as millions of cells within our body regenerate second-by-second through what is an essentially automated process, perhaps healing in general was simply something that our bodies did naturally when not disrupted or hampered in some way. I came to understand that the essential thing to do—very nearly the only thing we could do—was to create the conditions that would allow natural processes to unfold to their fullest extent, without disturbance from things like chronic stress, excessive stimulation or the ingestion of harmful foods and drinks.
This basic principle—doing what we can to enact ideal conditions for self-healing while minimizing harmful disruptions—lies at the very heart of East Asian medicine as it is generally practiced in Japan, China and beyond. Though rarely articulated at this level of abstraction, the daily nutritional choices and other health-related behaviors of contemporary Japanese people (including those that have to do with temperatures) still reflect this central principle and it is through this lens that they can be situated and understood as a coherent whole. Part of an expansive field of richly diverse practices, the underlying system of healing views nature’s energy (expressed as ki in Japan and chi in China) as immensely more powerful and superior to anything that humans might themselves invent or implement. This means that even medicinal herbs, central as they are for Eastern medicine, are administered with great caution and moderation, so as to avoid negative effects from excessive energy. Humans may seek to borrow from nature’s wisdom and power, but we must do so from a position of humility and great care. In the final instance, Eastern traditions hold that the natural flows of energy and unimpeded healing processes ultimately sustain health and vitality. This transcends the restoration of health after disease: those who engage in resonant practices can hope to reach tremendous levels of vitality, energy and thriving well beyond minimal standards of health, defined as the absence of illness.
Although too vast a topic to properly explore here, the more one begins to engage with Eastern healing beliefs and practices, the more one starts to also question the role of the self in relation to healing. Could it be that genuine self-healing can only unfold when we side-step, or overcome, our conventional or habitual focus on the self and the ego? Perhaps a more helpful way to understand ‘self-healing’ as a phenomenon is through a paradoxical inversion of terms: rather than perceiving it as a process of ‘healing by yourself’ or ‘through a self-led practice or process’, it seems to be equally—or perhaps even primarily—about ‘healing from the self’ and from its afflictions. A part of me was left with a strong intuition that it was only through reducing the centrality of the self could we allow organic healing processes to reach their fullest potential.
Through all these experiences and reflections, my friends’ preference for sayu over water with ice began to make a lot more sense. Even if the drinkers themselves could not always fully articulate the underlying philosophy, theirs was a practice that sought to be in tune with the body’s naturally occurring processes and energies, causing the least amount of disturbance and stress on internal organs and the body as a whole. With time, I have also personally become more attuned to how it feels to ingest drinks of different temperatures and I pay much more attention to keeping myself warm as the seasons change, especially when short on sleep or healthy food.
In the meantime, even as adjustments such as these tend to be made by individuals in the context of private lives, I have noticed that in some cases their influence can reverberate more widely, encouraging social change. Beyond merely fulfilling their own preferences and protecting their own bodies, perhaps my sayu-drinking friends are subconsciously quietly reshaping their wider environment by gently prompting others to get curious about what they ingest and why. With a bit of luck, maybe even the baffled restaurant staff asked to serve warm water instead of cold drinks will one day start inquiring into the healing secrets concealed in a plain cup of sayu.
*I would like to thank my wife, Eri, for first opening my eyes to Eastern healing systems — including the subtle benefits of sayu — and for so beautifully embodying that wisdom in her own gentle way of being.
Tuukka Toivonen, Ph.D. (Oxon.) is a sociologist interested in ways of being, relating and creating that can help us to reconnect with – and regenerate – the living world. Alongside his academic research, Tuukka works directly with emerging regenerative designers and startups in the creative, material innovation and technology sectors.
¹ There is a vast health literature in Japan that echoes this belief. For instance, the highly regarded immunologist Toru Abo (1947-2016) elaborated as follows: “Since energy is utilized more easily when it is first burned or transformed, when you’re deprived of heat you waste energy. In other words, if your body is cold, you need a certain amount of energy to warm it. Wearing something that makes your body cold, staying too long in a cold environment such as an air-conditioned room, or making your intestines cold by drinking too many cold drinks all cause you to lose energy. If you’re already in a weakened state, this can lead to illness.” (From Toru Abo’s Secret of Immunity, 2020, p.31)
