"All restrictions removed on your advance northward."{227} This message from General Buckner reached General Geiger, commander of III Amphibious Corps, on 3 April as the 6th Marine Division was approaching the Nakadomari Ishikawa line. The message marked an important change in the Okinawa plan. Originally, as part of Phase II, the capture of Motobu Peninsula and the neutralization of northern Okinawa were to come after the seizure of southern Okinawa. General Buckner's order placed the northern operations in the first phase and permitted the III Amphibious Corps to attack the enemy in the north while the XXIV Corps was closing with the Shuri defenders in the south.
There were good reasons for attacking northward without delay. The sooner this was done the less chance the enemy would have to organize his forces and fortify his positions. Colonel Udo, commander of the Japanese forces in the north, was known to be organizing the Okinawans for guerilla warfare. There was also the threat of counterlandings in the small ports of northern Okinawa by Japanese moving in from other Ryukyu islands or from Japan itself; by securing the ports this threat could be removed{228}
By early afternoon of 4 April columns of the 6th Marine Division were moving down off the high coral cliffs that overlook Ishikawa Isthmus, the narrow waist of the island leading off to the north, and were advancing to the long beach that faces the sea at the town of Ishikawa on the east coast. Here the forces of the division gathered. The marines were footsore and weary, but their spirits were high. North of the Nakadomari-Ishikawa line scattered groups of Japanese were straggling toward Motobu Peninsula; south of it American tanks were moving up to assembly areas while engineers were organizing dumps and bulldozing wide roads toward the isthmus. (See Map No. 17.)
This "rear area" work by the engineers was vital, for the advance up the isthmus was to be primarily a logistical effort. From the Nakadomari-Ishikawa line to the base of Motobu Peninsula there were two narrow roads, one along each coast, which were difficult to widen because they frequently ran along sea walls or wound around steep hills. Aerial reconnaissance had indicated that many bridges were out. Between the coastal roads was a rugged mountain range, covered with brush and grass. At long intervals roads and trails crossed the isthmus. The 6th Marine Division's hardest task was to move troops, vehicles, supplies, tanks, and guns over these one-way roads without losing the momentum that had been moving the division ahead at the rate of 7,000 yards a day.
The advance up the isthmus was spearheaded by the 22d Marines. Its tank-infantry teams moved along the coasts, making short patrols inland. Along the high ground in the center its 1st Battalion proceeded more slowly, patrolling trails and intercepting enemy stragglers. When the 22d reached the Atsutabaru-Kin line, the regiment paused while the 4th Marines passed through on the east and the 29th on the west. The marines encountered only stragglers except during the night of 5-6 April, when from thirty to forty Japanese blundered into their lines and were killed or driven off.
Both regiments continued to advance with great rapidity. The division prescribed a method of leapfrogging that at the same time freed the roads and provided security. As the battalions pressed ahead, platoons peeled off to patrol in advance or on the flanks. Their mission completed, they returned to the rear of the column. Trucks and supplies followed swiftly as engineers cleared roads and repaired bridges. LVT's and LST's waited for the troops to secure likely inlets or bays where they could unload.
The 29th Marines reached Chuda on 6 April and threw a line across the isthmus on the road there. In its sector the enemy's destruction of bridges had been inept; frequently only a span of the bridge had been dropped or cracked. The engineers cut hasty bypasses for the vehicles, repairing the broken spans later. The 4th Marines, however, was delayed by blown bridges, since destruction had been more effective in its sector on the east coast; at one point engineers had to set in a 120-foot bridge.
Map No. 17: Advance in the North (6th Marine Division)