Nicknamed "The Human Weapon", Du-Ri also played in the 2002 World Cup, but as a forward, and has since converted to defence and is now noted for his willingness to join attacks.

BBC: South Korea defender Cha Du-Ri seals Celtic switch

Traditional rules of engagement stipulate that a human must decide if a weapon is to be fired.

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" Since string made possible everything from warm clothing to ocean-going boats, it served as "the unseen weapon that allowed the human race to conquer the earth.

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