Marshal Dmitri Yazov, former minister of Defence of the Soviet Union, said he was deeply moved by Kim Jong Il's outstanding military wisdom, ingenuity and profound military knowledge.

Kim Jong Il completely acquired existing military ideas and theories and was well versed in the latest military science and up-to-date military hardware.

He authored many works on military affairs, which dealt with the principles of Juche-based military ideas, their fundamental features and advantages, factors of victory in war, the building of services and arms, combat methods, etc.

His military knowledge covered all arms ranging from tank to plane.

The knowledge caused admiration even from foreign military scientists.

When Kim Jong Il visited Russia in 2001, Russian President Vladimir Putin showed him Khrunichev Space Science Center, Omsk Transport Machine Factory and Chkalov Air Production Complex, which were not open to other heads of state. Guiding him, Russian officials were astonished by his deep insight into the advanced military science and technologies and military hardware.