纸上谈兵

lit. military tactics on paper (idiom) / fig. theoretical discussion that is worse than useless in practice / armchair strategist / idle theorizing / cf Zhao Kuo 趙括|赵括[Zhao4 Kuo4] leading an army of 400,000 to total annihilation at battle of Changping 長平之戰|长平之战[Chang2 ping2 zhi1 Zhan4] in 260 BC

used in 上聲|上声[shang3 sheng1]

(bound form) up; upper; above; previous / first (of multiple parts) / to climb; to get onto; to go up / to attend (class or university) / (directional complement) up / (noun suffix) on; above

surname Tan

to speak / to talk / to converse / to chat / to discuss

variant of 紙|纸[zhi3]

paper / CL:張|张[zhang1],沓[da2] / classifier for documents, letter etc

soldiers / a force / an army / weapons / arms / military / warlike / CL:個|个[ge4]