East of the Yamal, the route north of the Taimyr Peninsula proved impossible or impractical. East of the Taimyr, from the 1630s, Russians began to sail the Arctic coast from the mouth of the Lena River to a point beyond the mouth of the Kolyma River. Both Vitus Bering (in 1728) and James Cook (in 1778) entered the Bering Strait from the south and sailed some distance northwest, but from 1648 (Semyon Dezhnev) to 1879 (Adolf Erik Nordenskiöld) no one is recorded as having sailed eastward between the Kolyma and Bering Strait.