1. Even though Japan's surrender in August 1945 (with the surrender ceremony held on September 2, 1945) there were still many soldiers who were unaware the war had ended or refused to believe that Japan had surrendered. The most famous of the Japanese holdouts is Hiroo Onoda. He was a Japanese soldier that did not know that World War Two was over and kept fighting in the Philippines until 1974. More about him can be found on wikipedia and No Surrender Japanese Holdouts.
2. Company presidents in the United States commonly make 100 to 200 times as much as the lowest paid employees do. In Japan they are not paid nearly as much; they are generally paid 10 to 20 times more than the lowest paid employees in the company.
3. In 1923 there was an enormous earthquake in the Kanto region of Japan (which includes Tokyo) that killed around 140,000 people. To remember and prevent a disaster of that scope, September 1st had been designated, in 1960, as Disaster Prevention Day in Japan. On Disaster Prevention Day people listen to safety lectures and practice fire and earthquake drill are held. How effective these drills are is very debatable since all the participants were informed of the drill days in advance (which is very common for drills held in Japan, some schools, besides the days in advance warning, even give via intercom 5 minute warnings that a drill is about to happen). Random drills maybe more effective preparation but they have the annoying side-effect of disrupting class and being disorganized.
4. A bit on Japanese names. In Japan the family name comes first followed by the given name with no middle names. Names are usually written in kanji and often have a meaning. Since the kanji can have many different pronunciations it is common for people to write their names in kana form as well as the kanji form to avoid confusion. There are rules in naming your children, only officially sanctioned kanji can be used and the government will not allow names deemed to be inappropriate. It is very difficult to legally change your name, though not impossible. The easiest way it to convert (or pretend) to Buddhism and acquire a Buddhist name.
5. In the Heian and Kamakura period, it was common for samurai warriors prior to dueling to tell one another their full names, social rank, and to boast about their (and their ancestors) battle prowess. This had several purposes such as unnerving their opponent, raising their reputation, knowing whom they were fighting, etc. --This is what Tatewaki was referring to in his first battle with Ranma when he said it is custom in the Ranma ½ series.