為什麼日本是侵略者？

日本之所以成為入侵者，有很多原因。首先是本身資源不足，日本是個島國，沒有天然資源，在美國入侵日本後，日本明白要改革才會令國家富強，所以對外侵略，以取更多資源，那對國家富強有很大的幫助。因為這樣，所以日本人很著重資源消耗。
其次是因為明治維新前，日本是幕府年代，好多武士，講求戰鬥。明治維新後，武士仍然在國內有勢力，日本入侵中國是因為想轉移國內武士視線，鞏固天皇在國內的地位。故在晚清時，日本入侵了朝鮮。
及後二九年世界經濟大衰退，日本經濟嚴重受損，日本為了轉移國內不滿聲音，就提出入侵中國的策略，即是「田中奏摺」。所以日本成為了入侵者。

Before the Second World War, almost all countries in Asia were being colonised by the West. Japan was perhaps the only country which had never been colonised because of Meiji Modernisation.
Under colonisation, Asians were being racially discriminated, Asian resources were being exploited for the economic benefit of the West.
As it had already been highly industrialised, Japan viewed himself as the big brother in Asia, other Asian countries were his younger or weaker brothers.
According to the Japanese concept of an orderly society, order could be established if the young obeys the elderly, the junior follows the senior, the wife listen to the husband etc. It was very similar to the Chinese Confucianist thinking. Furthermore, the Japanese believed force from the elderly or the senior could be used against the younger ones in order to restore the order. When all the brothers, young and old, perform their role properly, order will be restored and enjoyed by everybody.
In view of the fact that most Asian countries were mere colonies of the West before the Second World War, Japan, looking upon himself as the bigger brother in Asia, intended to free his younger brothers from colonisation by force and to establish an Great East Asian Economic Prosperity Sphere so as to counter the influence and economic exploitation from the West. Violence was used in order to achieve this goal.
The bringing down of colonial governments were by way of military force and occupation with cruelty against the native people. especially those who were anti-Japansese. Therefore Japan became 侵略者.
In this reply, I have not considered 侵略者in its economic sense or cultural sense from 1970s till now as I believe 侵略者 is neither a relevant nor appropriate term in both senses.

日本是侵略者因為:
日本一直被外國國家食住,直到明治天皇作出明治維新,日本成為強國,便先侵略琉球群島,再侵略朝鮮半島,再打中國,以擴大自己的版圖。