A conflict in Japan's history which had an impact on their political developement ?

Question:

A conflict in Japan's history which had an impact on their political development.
Its for a grade 8 social class project

Answer:

Here's the keys;

Commodore Perry on Kuro-fune (Black Ships) achieved Kaikoku (opening of Japan) - Edo period -
http://en.wikipedia.org/wiki/Black_Ships
http://www.history.navy.mil/branches/tea…

Bunmei-kaika (Rapid Modernization=Westernization) - Meiji period -
http://encyclopedia2.thefreedictionary.c…

---- Edit:
WWII and Japan's 'rebirth' - Shouwa period
GHQ's control after the war (GHQ = Supreme Commander of the Allied Powers)
Although being completely devastated after WWII, it was a good opportunity for Japan to rebuild the country, introducing some ideas/actions led by GHQ. Massive production, for example, is one of the big effect. GHQ's actions led MacArthur to be viewed as the new Imperial force in Japan by many Japanese political and civilian figures, even being considered to be the rebirth of the Shogun style government which Japan was ruled under until the start of the Meiji Restoration Period.

http://en.wikipedia.org/wiki/Supreme_Com…
*GHQ's control was also targeted on 'brainwash' the Japanese (see 2 Media censorship)