International audienceDuring the court journey to Edo (Tokyo) in 1826, the famous Japan explorer Philipp Franz von Siebold (1796–1866) met an old and wise mathematician, explorer, and ethnographer, Mogami Tokunai (1755–1836). Tokunai not only allowed Siebold to copy sensitive maps of disputed territories in Northern Japan, but also donated him a set of 45 Japanese wood samples, most of them decorated with paintings of the foliage of the trees from which the wood came, and later provided with interesting notes on their timber uses by the Ainu people in “Jezo” (or Ezo-chi, more or less equivalent with modern Hokkaido). Based mainly on earlier detailed studies by Prof. Takao Yamaguchi and Prof. Nobushige Kato, we will discuss this collection i...