In 1826, Mogami Tokunai came to see Von Siebold in Edo, where he was staying at the time. According to Von Siebold, Mogami was an expert in mathematics and related sciences. Together, they discussed many scientific subjects and a close relationship based on mutual trust was established. Mogami lent Von Siebold a map of the Ezo sea and Sachalin Island (Karafuto).
This digital media file - and/or the physical objects depicted on it - originates from the digital and/or physical collections of the <a rel="nofollow" class="external text" href="https://www.kb.nl/">Koninklijke Bibliotheek</a>, national library of the Netherlands.