Shinkai studied Zen in Japan for over 7 years and is certified as a senior Zen teacher in the Hakuin-Inzan line of the Rinzai tradition. He has also practised under the direction of Soto Zen teachers.

While living abroad Shinkai studied a wide range of East Asian and Indian styles of yoga, both within the monastic setting and outside of it. In two monasteries he served as the resident taiso (body exercise) instructor. His teaching style integrates this experience and emphasizes being grounded and awake. Shinkai has taught yoga for over 7 years to a variety of groups including kids, elementary school teachers, university students, people who are vision or hearing impaired, and elderly folks. He encourages teachers to explore creating their own style and to find their own niche.

In 2014, Shinkai and his students founded the Blue Cliff Zen Center in Eugene, Oregon. It is dedicated to offering everyday people with yoga classes, mindfulness courses, and a Zen meditation group.