His collection of Chinese stamps and postal history was exceeded in importance only by that of Sir Percival David.
[3] His collection of Chinese stamps and postal history rivalled and in some areas exceeded that of Sir Percival David,[3] whose collection, sold by Robson Lowe between 1964 and 1975, is thought to be the most important ever assembled.
His last book, completed just before his death, was his account of Korean postal history from 1884 to 1905, originally published in Japanese in 1993.
In the forward he explained that it was partly a response to the failure of the official Japanese Post Office book celebrating the 120th anniversary of the postal service in Japan to mention Korea, despite the great effect that the Japanese have had on the history of Korea.
[5] The book won Large Vermeil medals at the Bangkok 93, China 96 and Pacific 97 philatelic exhibitions.