Sgt Kim Jae-kyung stands, unflinching, outside the Colombian embassy in Seoul, dressed in full military gear. The day before, he was in front of the Dutch embassy. The day before that, it was the Greek. This one-man demonstration by the former special forces soldier is his way of showing gratitude to all 22 countries who sent troops or medics to support South Korea after it was invaded by its neighbour North Korea in 1950. Now he wants his country to help Ukraine, following its invasion by Russia in February 2022. "We are lucky enough to now be the 10th most...