The 4th Tank Regiment, which had become separated from the 3rd Tank Regiment, advanced upon an objective under the cover of a thunderstorm that masked their movements but exposed the Soviet positions. The 4th Tank Regiment continued to advance, when suddenly a shift in the lightning flashes illuminated the advancing Japanese tanks, whereupon the Soviets immediately opened fire with anti-tank guns, heavy machine guns, and artillery. However, the range was so close that the Soviet artillery could not depress their guns far enough, and the 4th Tank Regiment was ordered to charge at about 0020 hours (12:20 AM). Soviet shells passed wildly over the charging tanks as they penetrated over a thousand yards into the Soviet lines. Now isolated, and deep within the Soviet lines, the 4th Tank Regiment moved several thousands yards where they met up with Japanese infantry.