Under the Tokugawa rule a treaty was concluded between Japan and Russia recognizing Karafuto (Sakhalin) as a joint possession of the two empires. Later the Edo government sent an envoy to St. Petersburg with a proposal that the 50th parallel of north latitude should be the boundary between the two countries. No final decision was arrived at, however, on that occasion, and it was resolved that each country should send an ambassador to Karafuto the following year to survey the island and determine the boundary. But domestic embarrassments so beset the shōgun's government that the promised envoy was not sent from Japan. In 1866 there was talk of dispatching an ambassador for the purpose, but nothing was done, while Russia was gradually pushing southward, until she finally encroached upon the region indisputably recognized as Japanese territory. The government of the shōgun was powerless at the time to offer any opposition, and shortly afterward it had to surrender the administration to the emperor. His majesty's ministers now proposed, through the intermediary of the United States, that the parallel of 50° north latitude should be taken as the boundary, but the Russian government rejected the proposal. Subsequently, Admiral Enomoto was sent as Japanese representative to St. Petersburg, and after much discussion it was decided, by a convention concluded in 1875, that the whole of Sakhalin should become Russian property, Japan receiving in exchange the Chishima Islands (the Kuriles).