Our friend and colleague Naoyoshi Suzuki (23 May 1931 to 11 Feb 2009) is dead.

However, he lives in our memories since he established the long-lasting Japanese–German cooperation on Protozoan diseases, and he was a well-beloved friend in our life during the last 32 years.

Naoyoshi Suzuki graduated in 1955 with a degree of Bachelor of Science at the Obihiro University of Agriculture and Veterinary Medicine in Hokkaido, Japan.

After years of practical experience in Aomori and research in Tokyo, he received his PhD at the University of Tokyo. Starting from 1966, he ran his career as a professor at the Obihiro University where he directed during the years 1973–1995 as full professor in the Department of Protozoology and Immunology. Due to his excellence on the important field of parasitic diseases in animals and humans, he fulfilled additional professorships at the Tokyo University (1989–1992), Gifu University (1990–1995) and Kitasato University Aomori (1995–1997).

In the year 1990, he founded in Obihiro the “Research Center for Protozoan Molecular Immunology”, which was named in the year 2000 “National Research Center for Protozoan Diseases”.

He directed this centre from 1992 to 1995 and promoted it with high energy so that it became one of the most important Centers of Excellence in Japan. Since 2007, this institution harbours the recent OIE Reference Laboratories for Equine Piroplasmosis, Bovine Babesiosis and Surra.

Naoyoshi Suzuki was a world-open personality, who established contacts to many international groups in his field of research, wherein he published more than 130 articles in English and many others in Japanese besides several book articles. One contact, however, impressed him for his whole career. This occurred during his research years (July 1966–1968) that he spent at the Department of Medical Parasitology in Bonn, where he cooperated intensively with Prof. Dr. Gerhard Piekarski—one of the important leaders of the German Parasitology. Both Naoyoshi Suzuki and Gerhard Piekarski appreciated each other from the early beginnings onwards. They were both hard-working scientists, and both were fascinated with parasites (Fig. 1).

Their close friendship led to the foundation of the Japanese–German Society of Protozoan Diseases. The opening ceremony was held on the 16th October 1977 in the International House of Science in Tokyo with the participation of Prof. Dr. G. Piekarski, Prof. Dr. E. Scholtyseck (Bonn), Prof. Dr. H. Mehlhorn (Düsseldorf) and Dr. G. Pelster (Bonn). This first meeting was followed by many others, which were held ongoing until today at 2-year intervals either in Japan or in Germany. The 17th one, at which Nao-San was missed due to his severe disease, was organised in September 2008 in Göttingen by Prof. Dr. Groß and PD Dr. Lüder. The importance of these meetings was not only based on the short information given on the recent status of research in both countries but these meetings also introduced a constant exchange of ideas between scientists. Thus, many German colleagues (e.g. Rommel, Hannover; Heydorn, Berlin; Mehlhorn, Düsseldorf; Seitz, Bonn; Heydrich, Munich; Janitschke, Berlin; Schmahl, Bochum; Karanis, Köln; Entzeroth, Dresden etc.) were guest professors in Japan and also sent also German colleagues to Japan. They also offered laboratory places to young Japanese scientists in Germany, who are now directors in Japan (e.g. Prof. Dr. Ono, Tokyo; Prof. Dr. Igarashi, Prof. Dr. Omata; Obihiro etc.).

This exchange from both sides was greatly supported by the Japanese Society of Promotion of Science and the German Humboldt-Foundation, where two names have to be mentioned as supporters: Dr. Kida (Ministry of Education, Japan) and Dr. Pfeiffer (Alexander von Humboldt-Stiftung, Germany).

The organisation of the meetings was and is furthermore substantially supported by the German Research Foundation (DFG), thus recognising the enormous common advances in the research of protozoan diseases.

Nao's world-open mind and his success in science and in research organisation made him a world-wide renowned figure, and he was honoured at many places in the world. Thus, Obihiro University honoured him by appointing him as President (2002–2007).

The Japanese Government honoured him the “Japan Prize of Agricultural Science” (1993), the “Purple Ribbon of Medals of Honour” (1994) and the “Order of the Sacred Treasure” (2008). Germany recognised his personality by awarding him with the “Verdienstkreuz 1rst Class” and Mongolia by the “Mongolian Award Cross”. The German Society of Parasitology is proud to have had Nao as “Honorary Member”.

Nao-San's life was always backed up by his family, which always supported strongly his activities and often joined him on his travels. His wife Kiyoko and his daughters Naomi and Mari also held close contacts to the families of many German scientists (Fig. 2).

Fig. 1
figure 1

Photo obtained during the 1990 symposium held at Bonn and on occasion of the 80th birthday of Prof. Dr. G. Piekarski

Fig. 2
figure 2

Nao-San, his wife Kiyoko and his younger daughter Mari on the anniversary day of the award of the German Verdienstkreuz first class

We all appreciate deeply this friendship and will keep him in mind. Nao-san is gone, but he lives in our memories.

We speak in the name of many German scientists who were guests and cooperators. Michel Rommel Alfred-Otto Heydorn Heinz Mehlhorn (Hannover) (Berlin) (Düsseldorf)