A formative part of his development took shape in the work of Kiiko Matsumoto, with whom he learned the hands-on, palpation-based style of Japanese acupuncture. Alongside this he immersed himself in Neijing Nature-Based Medicine at the Xinglin Institute, where the classical texts and their practical application are central. These two strands — sensing what the body has to say, and listening to what the classics teach — run through his work.

He completed the master's programme in Oriental Medicine (Research and Practice) at Middlesex University in London. Research continued to play a part afterwards: he was involved in the research work of the ETCMA and in several committees of the professional association Zhong. Within his field he has paid particular attention to Kiiko Matsumoto acupuncture, Japanese moxibustion, paediatric acupuncture and oncology acupuncture.

John has run his own clinic since 2007. He has also worked in community clinics in the Netherlands and the UK, and in care for Ukrainian refugees.

Teaching, learning and sharing knowledge are inseparable for him. He has taught and lectured at home and abroad, including at Oxrider Academy, the Rothenburg TCM Congress, the Northern College of Acupuncture and Zhong. John works in Dutch, English and German.