Can you read japanese? I found some websites explaning the difference between 闘う and　戦う http://mobile.cocoroe.jp/e/11637 http://alphatxt.cocolog-nifty.com/blog/2009/03/post-bc33.html http://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q1214861642

戦う > group(ex:war, game) 闘う > person(ex:wrestling, boxing)

「戦う」－general.　you 戦う in the war or at soccer game 「闘う」－when you try to get over something difficult, traubles, you 闘う(struggle). 「びょうきと　たたかう」(check this kanji 闘病) you　may also 闘う with your boss when you want to be promoted.