In August, 1958, the deputy chief-of-staff of PLA Zhang Aiping and the deputy commander-in-chief of PLAN Luo Shunchu (罗舜初) led a military delegation to visit former-Soviet Union signed a deal with Soviets to produce three types of Soviet torpedoes in China.

Everything appeared to be great but the subsequent Sino-Soviet split ended the promising future: from July 28 to September 1, 1960, former-Soviet Union had quickly withdrawn all of its advisors from China.

Compounding the problem, other domestic political turmoil such as Great Leap Forward further hindered the Chinese development of torpedoes.

In July, 1962, researchers at 705th Institute concluded that despite having samples and design drawings, compressed oxygen powered torpedoes was unsafe and after numerous accidental explosions, they were rarely used by the Soviet Navy, and Chinese navy was not happy with oxygen powered torpedo either.

The electrically powered Yu-4 torpedo program was put on hold despite the earlier successful development of components.

Further tests in September, 1979 indicated that the last two problems still existed: the high level of noise generated by the motor and the accidental arming of the fuse.

However, after 78 sample torpedoes had been test fired in July, 1981, it was revealed that the problem of the fuse still existed despite drastic reduction of the occurrence, and more worked was needed.