After the declaration of a special military operation the Soviet government requested reasoning on the attack to the Japanese and themselves proceeded to send ships within the Sea of Okhotsk towards the Japanese naval positions. The Soviet government after not receiving correspondence back from the Japanese proclaimed the Japanese as warmongers.
The Japanese airforce soon attacked the Soviet navy in the Sea of Okhotsk launching bombings against their warships before engaging in naval warfare with the Japanese fleet. The Japanese both attacked the soviet fleet with their bombing runs and through submarine warfare picking off the smaller Soviet ships came in with an advantage once direct warfare between the fleets began. Once the battle took place the Japanese launched their land invasion from southern Karafuto into northern Sakhalin striking deep into Soviet control. The Soviet stations far outmatched by the Japanese invasion were quickly overrun with the Japanese using drones to take out Soviet resistance against the Japanese advance. After just over a week of fighting the Japanese took effective control of the north of Sakhalin whilst fighting against remaining smaller pockets of resistance within the island. The Japanese also began mobilising their troops in Chousen just as in Mongolia the Neo-Republic of China began their own special military operation within Mongolia with the goal of restoring order and lost territory. The Soviet military command sought to formulate a new plan after the disastrous start to the war with major naval defeats and the swift loss of their control in Sakhalin and knowing further Japanese attacks were likely to come just as the Chinese were sweeping through much of the empty Mongolian lands towards Ulaanbaatar. The Japanese persisted with attacks against the Soviets bombarding Soviet coastal areas in the Sea of Okhotsk as the Chinese began attacks along the border of outer Manchuria. With little established soviet defence within Mongolia, most of its major settlements are occupied by Chinese forces which continue to approach the Mongolian SSR’s capital. The soviets in response built up defences along the border of the Mongolian SSR in more defensible terrain.
The Japanese continued their naval bombardments of coastal cities and organised incursions into Kamchatka using the Chishima Islands as a staging point and occupying small coastal towns with soviet defences caught off guard by the Japanese Army. The Chinese would eventually halt their advance into Mongolia and days later the same is done in the Manchurian front with the Chinese soldiers entrenching themselves in preparation for Soviet counterattack beginning to fortify and dropping the plan of being able to easily sweep the regions now that mobilised Soviet troops are to be arriving. The Soviet response arrived days later with the Soviet air force attempting to conduct bombings over the Japanese home islands though Japanese air defence was able to deter the Soviet campaign. The Soviets on the ground proceed to launch troops towards the fronts in Mongolia and Manchuria to halt any remaining Chinese advance after they have dug themselves in. The Mongolian SSR’s capital has its army reinforced from before and the Soviets launch a counterattack against the Chinese troops and the Chinese acknowledging the highly indefensible terrain choose to counter themselves by sending in large numbers of troops in chaotic fighting against the Soviets to maintain the front. The Chinese counteroffensives continue to see some decent success against the Soviets in the continental theatre and continued Japanese naval and coastal warfare takes place. The Japanese internally use the war for their own nationalist image producing large amounts of propaganda based on the war. They launch a larger invasion into Kamchatka and with the peninsula difficult to reinforce the Soviets are still underpowered to fight against the Japanese Army on the peninsula. As winter sets in over the peninsula the Japanese halt their advance and dig in expecting an eventual soviet counterattack but continue aerial bombing campaigns against the soviets.

Internally the war in China had become highly unpopular despite the government’s efforts to make the Chinese war effort look as clean as possible. The dislike of the war expands to internal instability in protests taking the streets and in military garrisons in the Chinese cities soldier deserting and later riots within the streets take place. Still the Chinese army stays loyal to the government and continues the war effort without much effect from the internal instability. With the internal instability of the Neo-Republic of China, the USFSR attempted cyberwarfare to instigate a revolt within the Xinjiang region and planned to mobilise an army to cross into the region to support any revolting groups. The soviets eventually conduct the attack and cross the border into Xinjiang just as the Soviet lines in both Mongolia and Manchuria see a collapse and deep Chinese pushes into the territory. With continued instability within the Chinese capital, the Chinese National Guard is called in and in an incident with protesters attacking police, the National Guard massacres protesters outside the Forbidden City. The Japanese announce a condemnation of the incident soon after and the massacre within China only instigates further internal instability with the government nearing the brink of collapse as military regiments too start deserting and members of government coming under arrest by military members. Still, Japanese attacks against the USFSR persist, sticking with the strategy of coastal bombardments and bombings against Soviet positions by the sea. The Chinese fronts eventually collapse entirely as the country falls into internal revolution known as the People’s Revolution causing the Chinese government to essentially collapse and loyalist forces being left within only a few locations such as some urban centres. With the collapse of China the Japanese have their mobilised garrisons in Korea put on guard as China is knocked out of the war. The Chinese loyalist forces eventually make their way to Japanese ports where they surrender themselves seeing no hope against the Chinese revolutionary uprising. The Japanese still continue to hold their dominance in the war though have put themselves into a halting of the offensives. The Japanese soon called upon the USFSR for peace negotiations and put plans in place to pull out of Kamchatka as negotiations take place.

The Soviets send diplomat Mikhail Belyaev to Tokyo for the peace negotiations. Despite this the negotiations fail as the Soviets are adamant on keeping northern Sakhalin and not letting it be taken by the Japanese. The Japanese fortify Karafuto and continue military operations in the sea though now declare an end to offensive operations within the region. They instate unrestricted naval warfare and declare intention to sink any unauthorised vessel within the Sea of Okhotsk. The New Japanese Empire also contacts the League of Superior Sovereignty requesting membership into the alliance it sees as more ideologically aligned with the Japanese state. The Soviets commence further bombing campaigns attempting to damage Japanese installations in Karafuto and the home islands though still facing fierce resistance against Japanese anti air emplacements and air force. This is enough for the Japanese to launch their own air raids over Soviet Far East airfields and naval bases. The Japanese entered militarisation preparing the South China Sea Fleets and defensive forces alongside planning conscription for the war. The Soviets proceed to further reinforce the region and threaten the Japanese in the case of Japanese invasion of mainland Asia. With the rising tensions in the region between the two powers and more international interest in intervention into the conflict, the Soviets and Japanese once again entered negotiations. The negotiations continued to take place over minor fighting over the sea with the primary topic being the status of northern Sakhalin. The Japanese eventually conceded to letting northern Sakhalin become an international zone not under the control of either nation. The two nations eventually completed the Treaty of Vladivostok signed in 2121 ending the war.