What is North Korea's 'self-blasting' policy in Russia's war against Ukraine?

North Korean leader Kim Jong-un has confirmed the soldiers' "self-blasting" policy in Russia's war against Ukraine. The policy requires soldiers to take their own lives on the battlefield rather than being captured. South Korea’s intelligence agency estimated last year that around 15,000 North Korean soldiers were sent to Russia, with approximately 2,000 reported killed, as reported by AP.