Fearing the influx of Christianity and foreign forces, in the Edo period (1603–1867) Japan prohibited foreign travel by Japanese people and trade and traffic with other countries, apart from Korea, China, and Holland. In 1828, Philipp Franz Balthasar von Siebold, a German who had come to Japan to work as a doctor at the Dutch trading post, tried to take some prohibited items, including maps of Japan, back to Holland when he completed his posting. Siebold was deported and barred from returning to Japan, while Takahashi Kageyasu (1785−1829, popularly known as Sakuzaemon), the Japanese official from the Astronomy Bureau of the Shogunate who had given Siebold the maps, was executed. All in all, 50 more people were punished for the incident. This map of Ezo (present-day Hokkaido, also seen as Yezo) is believed to be the original of the map that Takahashi gave Siebold. It is almost identical to “Die Insel Jezo und die Japanischen Kurilen, nach einer Originalkarte von Takahasi Sakusaimon, Hofastronomen zu Jedo” (Ezoshima and the Japanese Kuril Islands, based on an original map by Takahashi Sakuzaemon, court astronomer at Edo), which was published as an accompanying map in Nippon, a seven-volume work about Japan by Siebold. There is also a label, believed to date from the investigation of the incident, bearing an inscription asserting that the map (that Takahashi gave Siebold) was an exact copy of this one. The map is affixed with an ownership stamp of the Shōheizaka Academy, which was the educational institution of the Edo Shogunate.