Manchuria
Everybodys eyes were set on Nonni River and Lungkiang city. Zhukov wanted to act as fast as possible as new artillery and tanks were on its way to Japan. The Japanese however would need time to familiarize themselves with the new hardware; time Zhukov would use to the utmost to prepare for his offensive across the Nonni.
Since 1938 a large part of Gulag inmates had been transported south to build new marshalling yards in as many cities and towns of the Trans-Siberian Railroad as possible but also new ammunition factories and various Military repair facilities in Siberia. The longer term goal was to link up the various becoming short duallines of Trans-Siberian Railroad to have a true dualline all the way from Moscow to Vladivostok.
At Vladivostok the Soviet Pacific Flotilla were receiving new Submarines shuttled across Siberia by train as was about everything else to supply the war effort that wasn't still procurable in Siberia itself or in quantity.
Arriving at Vladivostok the Submarine reinforcements along their warhardened Comrades soon proved themselves adept at sinking Japanese merchantmen carrying supplies from Japan to Korea. The IJN proved itself still rather inept to counter this.
By early February Zhukov felt ready to move; much to the surprise of everybody, except the Japanese on the Nonni where pontoonbridge sections had been assembled on the western bank, the attack came south of the Amur at Chenqing and from the defensive complex in front of Vladivostok and Lake Khanka.
At Chenqing Zhukov had built up a new Mechanized Division that moved south towards Suihua north of Harbin which would bring the Soviets northern prong into the back of the defences of Lungkiang. Still Zhukov had to rely on large Cavalry formations out of necessity due to a lack of trucks to maintain links to his forward troops. In essence those Cavalry being modern Dragoons/mounted Infantry.
Seeing the success of the new Soviet mechanized thrust south the Japanese decided to abandon the Nonni River and fall back on Harbin than wait for the Soviets to use their pontoonbridges to cross it. Zhukov hurriedly threw the pontoonbridges across the Nonni and soon his Mechanized Divisions were racing towards Suihua and Harbin.
Due to the lack of communications lines in Manchuria Zhukovs troops soon overran Army Airfields and depots along the Northwestern Railway leading to Harbin.
As the Japanese Western Desert Force that had held the Nonni Line withered away in the west the Kwantung Army was feaverishly building a defensive line on the Sungari River passing the north and west suburbs of Harbin.
Japan had tried moving an Infantry Division across the strait to Korea but a large number of the merchantmen had been sunk by Soviet Submarines operating in the area. Had the Soviets had a better operational control of its Submarines it could have sunk the majority of the Division. As it was it was bad enough.
Come Spring Zhukovs troops were on the Sungari having advanced the 300 km's from the Nonni and once again waiting for logistics to catch up with the forward elements.
Zhukov's mounted Infantry had suffered serious losses during the advance due to the Japanese well knowing its lack of heavy support weapons due to lack of trucks to move such. Horsedrawn artillery were of course available but not in the numbers wanted and as with everything else logistics being the Achillesheel of the Soviet Far Eastern Special Army. As the Japanese was just as badly off logisticswise they never was able to deal the blows to the Soviet mounted Infantry they needed to cut off the Tank spearheads and they were badly off due to the T-34's armour.
Now being in farmlands the Japanese could make more efficient use of their largely Infantry Army; the Soviet Tank tactics were not suited for the more closed terrain and the Infantry still on the march.
Zhukov had a bad time during Spring until the Soviet Infantry caught up with his Mechanized Divisions on the Sungari and to the south of it.