space diagonal meaning in Chinese

空间对角线

A chess piece of lowest value that may move forward one square at a time or two squares in the first move , capture other pieces only on a one - space diagonal forward move , and be promoted to any piece other than a king upon reaching the eighth rank
兵，小卒价值最小的棋子，一次可向前移一方格或在第一步可移两格，只能吃对方靠对角线前方的一个子，当到达第八级时可升为除王以外的任何一棋子