South Koreans' failure to North Korean sudden attack led to a fierce battle over a US intervention. However successful Inchon Landing Operations had triggered Korean war into a internationally involving conflict. The overall value over Inchon Landing Operations is up to the changes of the military situation and the possibility of the rollback to North Korea. So to speak, Inchon Landing Operations were not only successful themselves, but also caused tremendous characteristical changes for the Korean War.
However up to recently, someone says that Inchon Landing Operations have been overestimated. They assert that North Korean Army(NKA) foresaw the Inchon Landing and completed defenses against it. And it moved tactical retreat against the counteroffensive by United Nations Forces, That is to say, during the time required 13days from Inchon landing to reoccupy seoul, North Korean Army could have prepared against MacArthur's operations.
However if we consider that the tide of adjoining sea of Inchon is very high, the time required 13days from Inchon to Seoul was not a delay. And through investigation to the RG 242-the records sized by U. S. Military Forces in Korea- and the Russian Sources, we know that NKA didn't have a pre-recognition and a preparation against Inchon Landing Operations.
According to North Korea, NKA succeeded retreat tactical maneuvering and they preserved the main forces. but the number of war prisoners of NKA was over 60,000 immediately after Inchon Landing, then it is proved that NKA's tactical retreat was not a success.
As a conclusion, we know Inchon Landing was a completely surprise attack to NKA, therefore main force of them at the south korea was destructed. The Inchon Landing achievedp a brilliant success and the nature of Korean war had changed into taking the initiative.