To fill in the central part of the EUSAK front where the change of IX Corps boundary had created a gap in the line, the UN commander inserted the ROK II Corps with three divisions (ROK 6th, ROK Capital, and ROK 3d) forward. Immediately to the right of this new ROK corps sector, the X Corps continued in approximately its same position on the east-central front. Its ROK 7th and U.S. 25th Divisions remained on line, while the ROK 8th had advanced to the former sector of the Marine division in the wild Punchbowl country. At the far right of the UN line, the ROK I Corps front was held by the ROK 11th Division at the X Corps boundary and the ROK 5th along the Sea of Japan. By 1 May 1952, nine Republic of Korea divisions had been emplaced on the UNC main defense line, three more than had been there in mid-March. Throughout Korea in March and April there had been a general stagnation of offensive action on both sides because of fog, rain, and mud. In May, however, the Chinese launched no less than 30 probing attacks against the ROK 1st Division in the I Corps sector, without gaining any significant advantage. To the right, the enemy and the U.S. 45th Division traded blows in several patrol actions. In June, major EUSAK combat action was still centered in the 45th’s sector, but the following month was marked by sharp battlefront clashes in nearly all Eighth Army division areas. For a two-week period in July and August, heavy seasonal rains limited both ground and air action. With the return of normal weather, heavy fighting again broke out, this time concentrated in the I Corps sector. This action did not abate until late August, when the onset of the heaviest rains of the season again drastically reduced military operations. Communist ground activity in the spring of 1952 was marked by increased artillery support which resulted in telling damage to UN infantry and artillery positions. Thus, during May, the enemy expended approximately 102,000 artillery and mortar rounds against the Allied front, roughly 12 times the number fired the previous July, just prior to the period of stabilized battlelines in Korea. The artillery buildup was accompanied by a sharp decrease in hostile air support activities. While the Chinese had flown 3,700 jet sorties during the first month of 1952, by June the monthly total had dropped to 308.