Sakhalin was once a Chinese territory, but was first explored by the Japanese in the 17th century. In a trade for the Kuril Islands, it was settled by Imperial Russia in the 19th century, and exchanged hands from Russia to Japan and back to Russia again over the course of the 20th century and World War II, continuing to be a point of contention between the two nations.^[1]

20th century[]

Having initially planned to employ him as a cosmonaut, when the Soviet government discovered that Mikhail Rasputin was an energy-warping mutant, they instead sent him to investigate the Void on Sakhalin Island. Though he survived the journey, he disappeared inside for several years.^[2]

Modern age[]

After Magneto's detonation of a nuclear weapon in Russian airspace created an electromagnetic pulse which wiped out computers across the country, Matsu'o Tsurayaba and some collaborators within the Russian Army took the opportunity to unearth the hidden Omega Red undetected. Though he paid his collaborators for their help, Matsu'o then had his Hand ninjas kill everyone else involved to cover his tracks.^[3]

When the Void on Sakhalin began to show signs of a potential crisis, the Russian government contacted their Japanese counterparts as a courtesy, and the Japanese hero Sunfire was sent to assist in the investigation. Sunfire's nuclear flames activated the portal, and the X-Men's Gold Team arrived to help deal with the fallout.^[1]

While this location is consistently referred to as the "Sakhalin Islands" or "Sakhalin Isles" in comics, in reality it is a single island larger than the nation of Sri Lanka.