Rubuta ci gaba don wannan sakin layi - A lokacin Russo-Japan War, Japan ya iya mamaye da kuma mamaye
dukan tsibirin Sakhalin a cikin makonni da yawa a watan Yuli 1905. Ta hanyar Yarjejeniyar Portsmouth, wanda ya kawo karshen yakin, Rasha ta ba da rabin kudancin Sakhalin zuwa Japan (wanda aka haɗa a matsayin Karfuto Prefecture), yayin da sojojin Japan suka janye daga arewacinsa; don haka kasashen biyu a karo na farko a tarihin su sun raba kan iyakar ƙasa, wanda ya gudana tare da 50th layi daya arewa a duk tsibirin Sakhalin, daga Strait of Tartary zuwa Tekun Okhotsk. Kodayake Japan ta mamaye arewacin Sakhalin a cikin 1920-1925, a lokacin da kuma bayan Yaƙin Basasa na Rasha, an kafa ikon Soviet a arewacin Sakhalin a 1925, kuma layi na 50 ya zama iyakar Japan-USSR.