Workers at South Korea's largest bank are on their first nationwide strike in almost 20 years on Tuesday.<br />The walkout at KB Kookmin Bank comes as labor union and management failed to reach common ground... during their last-minute negotiations on Monday.<br />The union wants the bank to change its maximum salary policy, performance-related pay grade system and give workers profit-sharing bonuses in line with the industry standard.<br />With about a two-thirds of the bank employees on strike,... hundreds of branches are expected to be affected as well. <br />The union says.... four more strikes are scheduled through March,... if their demands are not met. <br />