On May 29, 1945, the 1st Marine Division conquered Shuri Castle, Okinawa. From the article:
"THE FINAL CAMPAIGN: Marines in the Victory on Okinawa
by Colonel Joseph H. Alexander, USMC (Ret)
Daybreak on 29 May 1945 found the 1st Marine Division beginning its fifth consecutive week of frontal assault as part of the U.S. Tenth Army's grinding offensive against the Japanese defenses centered on Shuri Castle in southern Okinawa. Operation Iceberg, the campaign to seize Okinawa, was now two months old — and badly bogged down. The exhilarating, fast-paced opening of the campaign had been replaced by week after week of costly, exhausting, attrition warfare against the Shuri complex.
The 1st Marine Division, hemmed in between two other divisions with precious little maneuver room, had advanced barely a thousand yards in the past 18 days — an average of 55 yards each bloody day. Their sector featured one bristling, honeycombed ridge line after another — sequentially Kakazu, Dakeshi, and Wana (with its murderous, reverse slope canyon). Just beyond lay the long shoulder of Shuri Ridge, the nerve center of the Japanese Thirty-second Army and the outpost of dozens of the enemy's forward artillery observers who had made life so miserable for American assault forces all month long.
But on this rainy morning, this 29th of May, things seemed some how different, quieter. After days of bitter fighting, American forces had finally overrun both outposts of the Shuri Line: Conical Hill on the east, captured by the 96th Infantry Division, and the Sugar Loaf complex in the west, seized by the 6th Marine Division. Shuri no longer seemed invincible.
Company A of the 1st Battalion, 5th Marines moved out warily, expecting the usual firestorm of Japanese artillery at any moment. There was none. The Marines reached the crest of Shuri Ridge with hardly a firefight. Astonished, the company commander looked west ward along the ridge several hundred yards to the ruins of Shuri Castle, the medieval fortress of the ancient Ryukyuan kings. Everyone in the Tenth Army expected the Japanese to defend Shuri to the death — but the place seemed lightly held. Spiteful small arms fire appeared to come from nothing more than a rear guard. Field radios buzzed with this astounding news. Shuri Castle itself lay beyond division and corps boundaries, but it was there for the taking. The assault Marines asked permission to seize the prize.
Major General Pedro del Valle, commanding the 1st Marine Division, did not hesitate. By all rights the castle belonged to the neighboring 77th Infantry Division and del Valle knew his counterpart, Army Major General Andrew D. Bruce, would be angry if the Marines snatched the long-sought trophy before his soldiers could arrive. But this was an unprecedented opportunity to grab the Tenth Army's main objective. Del Valle gave the go-ahead. With that, Company A, 1/5, swept west along the ridge against light opposition and took possession of the battered complex. Del Valle's staff had to do some fancy footwork to keep peace with their Army neighbors. Only then did they learn that the 77th Division had scheduled a major bombardment of the castle that morning. Frantic radio calls averted the near-tragedy just in time. Results of the Marines' preemptive action incensed General Bruce. Recalled del Valle: "I don't think a single Army division commander would talk to me after that."
Notwithstanding this inter-service aggravation, the Americans had achieved much this morning. For two months the Shuri Heights had provided the Japanese with superb fields of observed fire that covered the port city of Naha and the entire five-mile neck of southern Okinawa. Even now, as the Marines of A/1/5 deployed into a hasty defensive line within the Castle's rubble, they were oblivious to the fact that a Japanese rear guard still occupied portions of the mammoth underground headquarters complex directly under their muddy boondockers. They would be astounded to learn that the subterranean headquarters of the Thirty-second Army measured 1,287 feet long and as much as 160 feet deep — all of it dug by pick and shovel.
The Japanese had in fact stolen a march on the approaching Tenth Army. Most of their forces had retreated southwards during the incessant rains, and would soon occupy the third (and final) ring of their prepared, underground defenses, a series of fortified escarpments in the Kiyamu Peninsula.
Seizing Shuri Castle represented an undeniable milestone in the Okinawa campaign, but it was a hollow victory. Just as the flag-raising on Iwo Jima's Mount Suribachi signified only the end of the beginning of that prolonged battle, the capture of Shuri did not end the fighting. The brutal slugfest on Okinawa still had another 24 days to run. And still the Plum Rains fell, and the horrors, and the dying, continued."