It had a negligible outcome on anything at all. The most intense phase of the intervention came after Admiral Kolchak and most of the White Forces were already defeated, and the intervention devolved into a complete trainwreck that would be comedic if it wasn't so tragic.

The intervention in the Far East had its inception in the drama concerning the Czechoslovak Legion, a force of around 60,000 which had fought with the Tsar against the Austro-Hungarians in the name of creating a Czechoslovak homeland. After the collapse of Austria-Hungary and the Bolshevik revolution, the legion wanted to return home. However, on May 14, 1918, they entered a dispute with Soviet railway authorities as Leon Trotsky had ordered their train be stopped due to the need to transport Hungarian POWs West. They mutinied, seizing large stretches of the Trans-Siberian Railway and enabling monarchists to take control of much of Siberia. In the far East, most of the local authorities cooperated with the regime of self-proclaimed Supreme Ruler Kolchak. In July of that year, they seized Vladivostok and declared it an Allied protectorate.

Almost immediately, Kolchak's regime was beset by Soviet guerilla activities, and was perpetually on the verge of collapse in all sectors. In August of 1918, the Allied Powers, nominally under the leadership of Woodrow Wilson, agreed to deploy "25,000" troops to Siberia with the twin goals of "rescuing the Czechoslovak legion" and securing the East for White Forces, to become a base for operations Westwards (bear in mind World War 1 was still raging at this point, so the Czechoslovaks were potential manpower against Germany). At its peak, the "25,000" man intervention spiraled into one involving more than 80,000 troops. This was the result of the ambitious foreign policy of Japanese Prime Minister Terauchi Masatake, who coerced Wilson into letting the Japanese contingent of "8,000" operate under independent command. Terauchi had embarked on previous expansionist projects, including the Nishihara Loans to the Duan Qirui government in China. Ironically, Terauchi would be forced to resign only the following months by a rice shortage which led to riots.

From the beginning, the allied intervention, involving Canadian, American, Italian, Chinese, Japanese, and British troops, was engaged in a war against Soviet partisans. The ever-increasing Japanese contingent, which reached a maximum strength of 70,000, took the lead in this war due to its "proven" and aggressive counterinsurgency doctrine, which essentially amounted to tracking down insurgent bands and attacking them, or in essence waging an insurgency against the insurgent. This campaign rapidly devolved into an orgy of violence against civilians which foreshadowed Japanese brutality in the Second World War.

In February 1919, admiral Shiro Yamada of the 12th Infantry Brigade ordered the following:

First, extremists who oppose the Japanese and Russians are scattered around the area, but they sometimes attack our soldiers while pretending to be good people [non-combatants]. If there are any people in the village who are obscenely hostile to the [White] Russian Army soldiers in the future, the Russo-Japanese Army will acknowledge that the entire village is made of militants and burn it.

Later, diplomat Tsuneo Matsudaira, involved in the organization of Russian collaborator forces, declared the following:

Recently, in various parts of the country, Red Guards have infiltrated the civilian population. The Japanese army has encountered difficulty figuring out who are militants and who are civilians. It is becoming impossible to restore order, but such a situation must not be tolerated. When you discover militants, you should burn and destroy their village, regardless of the size of the village and its population.

Orders given both by Communist and Japanese forces ensured the war would degenerate into a series of massacres by both sides against alleged supporters of the other. In January of 1919, there was a partisan uprisign in the town of Mazanovo close to the Amur river. Japanese troops were forced to withdraw due to the extreme cold, leading to the village being temporarily occupied by Red Army partisans, who promptly executed White sympathizers. When the weather thawed, a certain Captain Maeda launched a counter-attack, burning random villages along the way and slaughtering peasants. Maeda then arrived in a nearby village called Sohachino, where his men shot most of the villagers as they tried to flee.

A Japanese army after action report following a subsequent raid on a vilalge called Innokenchevskaya stated, "The 12th Division, 3rd Battalion, 8th Company raided the village early in the day, and after the partisans fled, saw the civilians as partisan sympathizers. The men bayoneted and shot more than 100 people, while officers and non-commissioned officers decapitated numerous others using their katanas. After that, they looted goods, collected food, and set fire to the houses".

In May 1920, a partisan unit led by Yakov Tryapitsyn entered the multi-ethnic town of Nikolayevsk, inhabited by Russians, Koreans, Chinese, and a few Japanese. The Japanese soldiers, whose policy at this point in the war had become complicated by frequent and somewhat dishonest proclamations of neutrality, allowed Tryapitsyn to enter the town under a flag of truce. However, Tryapitsyn quickly started rounding up all the White sympathizers in town and shooting them. Knowing that Japanese troops had a reversion to the idea of surrender, Tryapitsyn then decided to force a battle with the Japanese by demanding they give up their arms. The badly outnumbered Japanese launched a surprise bayonet attack in response which resulted in many deaths on both sides and the obliteration of the Japanese garrison. Tryapitsyn then moved to massacre all the Japanese residents in the town, including the local consul. Some civilians managed to flee aboard Chinese gunboats. The catastrophe was enough of an embarassment to force the Japanese War Minister, Tanaka Giichi, to resign. Japan demanded compensation from the Bolshevik government, who agreed to execute Tryapitsyn. However, deciding this wasn't enough, Japan occupied oil-rich North Sakhalin until 1925.

These massacres took place against the backdrop of a complicated and (from an Allied point of view) ever-devolving political situation. Just days after the start of the allied intervention in August 1918, a Buryat-Russian officer named Grigory Semyonov, with the support of Czechoslovak officer MK Dieterichs, effectively took control of much of the Far East. He subsequetnly obtained Japanese support, creating tensions between the Japanese and Americans, the latter still supporting Kolchak. On the 14th of November 1919, Admiral Kolchak was driven by the Red Army from his capital at Omsk, and started a flight east to Allied-occupied territory. Along the way, he was constantly harassed by Red partisans, and his bodyguard deserted him. As a result, the Allies ordered the Czechoslovak legion to escort him. Instead, in February of 1920, the Czechoslovaks handed him, and most of the Imperial gold reserve, over.

The fall of Kolchak ended the need for intervention in the eyes of all the allied powers except the Japanese. In April 1920, the United States left Siberia, and that same month, the Soviets created the puppet "Far Eastern Republic" to operate as a buffer state between them and Japan. The FER in theory operated within Japanese-occupied territory, and had the tacit approval of several Japanese officers in the area. However, the Japanese in practice delegated authority to their proxies, Semyonov, General SN Rozanov, Ivan Kalmykov, and Amur Ataman Kuznetsov. In exchange, these proxies, especially Semyonov and Kalmykov, got to work plundering as much of the Imperial Gold reserve as they could from the Reds, other Whites, and Czechoslovaks, and handed over upwards of 1,200 kg of gold to the Japanese. Semyonov also busied himself proclaiming his designs for a greater Mongolian Empire, and distributing copies of Protocols of the Elders of Zion to Japanese troops.