Speaking of Zhang Xueliang, I am afraid that there are three things that have to be mentioned, in addition to the Xi'an incident and the Northeast Yizhi, the other is the Middle East Road incident. In July 1929, due to the issue of the right of way of the Middle East Railway between China and the Soviet Union, the "Middle East Road Incident" broke out, causing armed conflict.
The young marshal originally wanted to show his ambitions, but only then did he find that the soviet bone could not be gnawed.
So how could the Soviet Union have a railway in the northeast? This has to start after the Sino-Japanese War.
In 1896, Tsar Nicholas II held a coronation ceremony, and Russia asked Li Hongzhang to participate by name, which also opened his only overseas visit. When Li Hongzhang was in Russia, he signed the Sino-Russian Secret Treaty with Russia.
The Russians took advantage of the Qing Dynasty's intention to use the qing Dynasty to intimidate and induce them to obtain the qualification to build a railway in the northeast, and the ambitions of the Russians are self-evident, they are in order to swallow the northeast alone.
Sure enough, a railway did not feed them, and Russia forced the Qing government to sign a large lease treaty with them, and won the privilege of building a branch line of the Middle East Road (from Harbin to Dalian).
After the October Revolution, the Soviet government was established, and the Soviet Union twice issued a declaration on China, claiming that all unequal treaties in the Tsarist era were invalidated, and China was happy for a while, but we know that this attitude of Soviet Russia is actually out of its own interests.
In addition to ideological reasons, what is more important is that the Soviet government is facing the problem of the stability of the regime, a nascent socialist regime that makes the Western countries very hostile, and for the sake of the stability of the regime, the Soviet Russia had to give up the interests seized in the tsarist era.
However, with the change of the international situation, the attitude of the Soviet Union took a sharp turn. As we know, the Soviet Union not only did not have the idea of returning the Middle East railway, but even has been encroaching on China's territory.
In 1927, the Soviet Union wanted to transfer the Middle East Route to Japan. At the same time, the Nationalist government engaged in revolutionary diplomacy, and Zhang Xueliang, who succeeded Zhang Zuolin, ruled the northeast. He decided to forcibly take back by force the Soviet Union at the time of the management of part of the Middle East Railway. After all, the Northeast Army he owns, from the perspective of the card, the strength cannot be underestimated.
Of course, Zhang Xueliang also won the support of the central government, but he was only fooled. The Northeast Army was not a rival to the Soviet Union at all, and as a result, Zhang Xueliang was defeated miserably, and signed the "Boli Protocol" with the Soviet Union, not only did not come back, but also lost the Black Blind Island.
Of course, although the Northeast Army was defeated, we cannot ignore Zhang Xueliang's just move to safeguard national sovereignty, after all, without the backing of strength, it is impossible to succeed with a heart of blood.