there are some difference between this two character in usage: 打仗(√) 打战(×) at war, fight , fight a battle 战争(√) 仗争(×) war (battle, fight) when the character 仗(noun) means 'war'(there'er other meanings of 仗) , normally as the word '打仗'(verb): 那时两国正在打仗 At the moment the two countries were at war. 打胜仗 win a battle (仗 can be a fight ,a battle) and it doesn't particularly indicate a location,time,or the scale of war. 战(noun & verb ) 战争(noun): war 战胜(verb) :defeat,win ,beat, overcome when you indicate a certain war like WW II(二战) Civil War(南北战争)，you must use the character 战. and in Chinese, 战 usually be combined to the items which associated with war, like 战机(warplane) 战马(steed) 战场(battlefield) 海战(naval battle) 陆战(land battle)... When you don't know which one to select, just take 战 :p