二战中日本的武器只能算三流，为什么战斗力这么强呢？

无论陆海空，日军从来没有比武器水平更高的对手战斗力强过。

国军的火力差毋庸置疑，诺门坎都说苏军有装备人数优势，但是只是苏军后期反攻时明显。前期日军直到1939.7月初有主动权时，人数不比只有一万多的苏军少。日军依然没啃动苏军。论战斗力，日文维基上有一段引用承认野战重炮第三旅团（不是23师团二流部队）射击训练不如苏军，朱可夫也敢声称苏军炮兵射击方面强于日军，并且此时刚大清洗的苏军也认为日军高层的指挥很差。

马来亚英军飞机坦克数量远少于日军，菲律宾美菲军没有制海制空（但是巴丹支撑时间和后期日军守岛不遑多让），缅甸前期就英缅1师加英印17师面对日军33,55,18,56师团，兵力太少，有个装甲旅也无力回天。

二战日军在欧洲战场算什么水平?

太平洋正规美军认为日军射击水平和白刃战都不够好，柯林斯认为日军技巧上不足，不如德军和美军。

The German was far more skilled than the Japanese. Most of the Japanese that we fought were not skilled men. Not skilled leaders. The German had a professional army... The Japanese.. didn't know how to handle combined arms – the artillery and the support of the infantry – to the same extent we did. They were gallant soldiers, though... They fought very, very hard, but they were not nearly as skillful as the Germans. But the German didn't have the tenacity of the Japanese.

缅甸驻印军新38师112团跟美军5307团丛林战以少打多也击败得了王牌第18师团。英军钦迪特旅加驻印军新38师营级支援3000人可以劣势兵力拿下孟珙打跑53师团4个大队。

【图片】新一军相关【古德里安吧】_百度贴吧

冲绳日军离开洞穴坑道，组织反攻，战力原形毕露。趁美军不备一天打18000发炮弹，暂时还不算弹尽粮绝，交换比却悬殊至极。和被滩头海空火力炸得弹药发射量比日军更少，却交换比更好的安齐奥德军完全不是一个级别。

冲绳弹药，柏林弹药，战斗效率与战斗力之再谈

至于海战，日军的胜利亦多是飞机军舰装备性能优于前期的英美所致，远非靠三流装备战力多强。