6) Japanese myths and cultural elements
Sailor Moon's Japanese name (Tsukino Usagi) means "rabbit of the moon", specifically referring to an Asian legend of a rabbit on the moon pounding the mochi (a rice cake). There are several jokes based on this name: she wears and uses rabbit designs all the time; her hair visually suggests rabbit ears; Luna's computer password is "the rabbit on the moon pounds the mochi"; Chibi- Usa is referred to as "the rabbit" by villains (DIC even kept this a few times); Usagi's _least_ favorite food is carrots, etc. The jokes mostly go over the head of audiences who don't know about the original, though the North American version does claim (on the doll boxes) that her favorite animal is the bunny rabbit.
Some dubs in other languages translate her name to keep the jokes; for instance, in the French, German, and Italian versions she's named "Bunny". The Mixx comic book version also uses "Bunny".
The Japanese school system is uniformly 3 grades of mid- dle school and 3 of high school, so Serena is in the equivalent of 8th grade when in second year middle school.
Uniforms are standard for Japanese public schools, including sailor suits for girls in many places. Both boys' and girls' uniforms were derived from the uniforms worn by the Imperial Japanese Navy in the Meiji era (1868-1912).
There is a fierce high school and college entrance exam competition in Japan, and what college you go to ultimately determines a great deal of your standing in your whole life. The exams are nothing like entrance exams in America; they are long and involve a lot of regurgitation. Many students go to special cram schools (juku) for years solely to study for these exams; Amy goes to one (explained as "computer class" in the dub). School is very difficult, and students get hours of homework a day (having much less time for socializing than usually shown in Japanese animation), up to college; college itself is often easier than in America.
All Japanese students study English for years, but the English teaching system is one of the worst foreign language teaching systems in the world, and most Japanese can speak little English.
Sword, mirror, and jewel:
These items are based on the myth of the legendary three treasures which the sun goddess Amaterasu brought to Japan. They appear a lot in anime, showing up at least in Yuu Yuu Hakusho, GS Mikami, and Samurai Troopers (Ronin Warriors).