[6] A Yono-class submarine is thought to have fired the torpedo attack which sank a South Korean Pohang-class corvette, ROKS Cheonan on 26 March 2010 in South Korean waters.

[7] According to some investigators, the weapon used in the attack was a North Korean-manufactured CHT-02D torpedo, from which substantial propulsion parts were recovered.

The device allegedly exploded not by contact, but by proximity 6 to 9 metres (20 to 30 ft) below Cheonan, creating a powerful pillar of water, called the bubble jet effect.

They also dismissed claims regarding writings on the torpedo and clarified that "when we put serial numbers on weapons, we engrave them with machines."

The defector, known by the alias "Ahn Cheol-nam", stated that the captain, co-captain, engineer, and boatswain of the mini-sub which sank Cheonan had been awarded "Hero of the DPRK" in October 2010.