纸上谈兵 (紙上談兵) zhǐ shàng tán bīng

zhǐ shàng tán bīng set phrase military tactics discussed on paper; theoretical discussion that is useless in practice
Domain: Idiom 成语
Notes: (CC-CEDICT '紙上談兵'; CCI p. 25; Guoyu '紙上談兵')