Since ancient times in Japan, spiritual aspirants have used the coldest time of the year, from early January to early February, to conduct ascetic training to purify negative forces and obstacles and spur the development of mental discipline and other spiritual faculties. Negative forces don't necessarily imply negative spirits, but from a Buddhist perspective they can be seen as outward manifestations of greed, anger, or ignorant thoughts and behaviours that produce suffering. Such negative energies prevent us from turning our hearts and minds towards loving-kindness, and act as obstacles on our path to spiritual liberation and enlightenment. 

Masters Shinjo and Tomoji began a month-long period of intense ascetic training on 8th January, during the bitterly cold winter of 1936. The practice consisted of rising early, performing cold-water ablutions, and undertaking the Thousand Scroll Sutra practice, where participants chant the Heart Sutra one thousand times divided by the number of participants. The fewer the people the greater the number of times they chanted. At the conclusion of the training, Shinjo and Tomoji resolved to dedicate their lives to the spiritual care and well-being of others. 

*Excerpted from Sculpting the Buddha Within: The Life and Thought of Shinjo Ito, by Shuri Kido (Wisdom Publications, 2019), pp. 73 - 82.