March North

Thursday, March 24th, 2016

The open secret of the Korean War is that the US limited the South Korean army to just 100,000 men and didn’t allow them an air force:

[South Korean President Rhee] wanted Korea to be united and one of his favorite slogans was “March north”. The Northerners also wanted it united, but under other auspices. This led to a number of armed clashes along the 38th parallel. The Americans were concerned about his starting a war with the Chinese and perhaps the Russians involved and hence kept his army small (100,000 men with no air force). At the time this wasn’t a bad idea if it was assumed that the small size of his army, together with the fact that he was not given decent anti-tank weapons prevented his “March North”. Unfortunately it gave the north a wonderful opportunity of which they took advantage. The poor state of the American occupation army in Japan together with an almost pathologically stupid intelligence chief who consistently underestimated the northern forces led to the early success of the Northern armies.

Diplomatically the Communists negotiated an agreement, now publicly available, between Stalin, Mao, and Kim under which the invasion would start, China would enter and Russia would provide air cover. Their air cover, incidentally, led to almost the only time that American and Russian military men exchanged shots in the whole of history. After the start of the war, the Russians provided aircraft and training to air forces for both China and North Korea, and when their air forces were adequate for the rather minor operations intermittently carried out south of the Yalu, the Russian air force, which had been badly shot up, withdrew. All three of these air forces operated out of airfields in Manchuria, which we did not bomb. We prevented the ROK from having an air force until well after the armistice.


Oddly, we kept the restrictions on the ROK army. President Rhee introduced conscription and put a lot of men in camps, but we refused to arm them. As mentioned above, he wanted 2,400,000 men in his army, which would be about the proportion of the adult population that France, England, Germany and Russia mobilized for World Wars I and II. We kept him to 100,000 legally although General Van Fleet cheated on his orders from Washington and got it up to about 120,000. This restriction on the ROK army is the open secret of this chapter. It is almost entirely unknown in the United States. The North with a much smaller population put about 4 times as many men into combat.

Our intelligence listed the North Korean army also as about 100,000. It could have hardly been more wrong. Nevertheless, on the basis of this poor guess, our pre-war policy was not hopelessly stupid. I should, however, say that in my opinion the estimates were formed to support the policy, not the policy based on the estimates.

But when the war broke out and the superiority of the northern forces was obvious to every newspaper reader, we stuck to our policy and G2 stuck to their 100,000-man estimate for several weeks. At the time I was studying Chinese at Cornell, and when the newspapers said that Chinese soldiers had been captured in Korea, I realized that the Chinese were in. Thus beating G2 by several weeks. G2 took the view that they were “stragglers” although what they were straggling from was not stated. This error was one of the major reasons why MacArthur disposed his troops in the north in a formation with his right flank uncovered. Peng Te Huai took advantage of the gap.

The southern army remained limited to 100,000 men. General MacArthur asked for arms to raise it to 225,000 and Washington replied that they just couldn’t find the necessary arms. This absurd statement was believed, not only by the American press, but also, surprisingly, by General MacArthur. Further, when the Russian air force entered the war, G2 briefing officers made major efforts to convince the press that they were Chinese and Korean pilots who had been trained by the Russians and hence always used Russian on their radios. The Russians did eventually withdraw their air division that had been badly shot up. In the later part of the war Chinese and Korean pilots, using Chinese and Korean on their radios, took the casualties inherent in flying the Migs. We continued to prohibit the development of a ROK air force.

One of the extraordinary features of this situation is that there was little press criticism, or even mention of it.


Many years after the end of the war I met a former colleague in political section of the American Embassy in Korea at a Far Eastern Society meeting. I remarked that it was astonishing that most historians seemed to leave out this restriction on the ROK army. He responded, “Of course, he would have marched north”.

The restrictions remained on for a long while. The air force was kept weak to non-existent and post armistice precautions were taken to make sure that the petroleum supplies in Korea were very small. The ammunition supplies were also limited. Altogether the bad relations between the Republic of Korea and us continued.


  1. Grurray says:

    “the Russian air force, which had been badly shot up, withdrew.”

    The experiences of the F-86 Sabre vs the MiG-15 led John Boyd to develop his Energy-Maneuverability theory in the early 1960s. Despite being lighter and armed more lightly, the F-86 had a higher kill ratio. It was superior because of its ‘fast transient’ ability to transition from one maneuver to another faster than the MiG-15.

    The Sabre turned better at low speeds and high altitude and also at high speeds and low altitude — either extreme of the flight envelope, while the Migs were superior in the middle of the flight envelope. The Sabre’s pilots would slash at the margins to defeat the Migs.

    Boyd used that lesson to develop his overall grand strategy.

  2. Isegoria says:

    Reader might enjoy Whittle’s piece on “Forty Second” Boyd and the Big Picture.

  3. Adar says:

    When speaking of an 100,000 South Korean army do not think of an army in the conventional terms as understood. Think rather a poorly armed constabulary force without heavy weaponry. Men yes, but heavy weapons no.

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