Column: South Korea martial law declaration remains shrouded in mystery

South Koreans reacted with anger and defiance when their President abruptly declared martial law earlier this month. The ensuing turmoil was captured in an iconic image that shows an opposition party spokesperson grabbing the rifle of a soldier amid chaotic protests outside the parliament building in Seoul. Weeks later, Yoon Suk-yeol is suspended from duty following a successful move by the opposition to impeach him, but the reasons for his declaration remain unclear. Former NHK Seoul bureau chief Aoki Yoshiyuki considers some possibilities.