Of License Plates

Since I've arrived in Japan, I've been continually perplexed by one thing: Japanese vehicle license plates.  In relation to everything else, I'm sure this is a minor problem, but it really has kept me in a continuous state of bemusement, and so today, I've decided to fix it. I've asked friends, read articles, and after much research, I can finally say that I understand the basics.

Like all things related to the bureaucracy, it's unnecessarily complex. Here's what I've found:

1. License plates (or ナンバープレート), are issued by the national government except in certain circumstances. These primarily include when the vehicle is considered a small motor vehicle: for example, motorcycles. In this case, the license plate will be issued by the local municipal government.
2. Although plastic plates are being introduced, most plates are still made out of aluminum. The size of your plate and numbers will depend on the size of your vehicle.
3. The color of your license plate and numbers depends on how many cc's your car is.
• General vehicles (though at times 360 cc vehicles are included) receive license plates with a white background and green letters if they are for home/personal use. They receive a green background with white letters if they are for business use.
• Other light vehicles (below 660 cc) receive license plates with a yellow background and black letters if they are for home use, and a black background with yellow letters if they are for business use.
• Two-wheeled vehicles (bicycles, motorcycles, etc.) that exceed 250 cc are issued license plates with a white background, green letters, and a green border if they are for home use. The opposite is used for business use.
• Two-wheeled vehicles below 250 cc are issued license plates with a white background and green letters for home use, and the opposite if they are for business use.
• Otherwise, plates for official business (ambulance, etc.) are issued plates with white background and red letters. Though there might be a case where they have a red background and black letters (as in police officers).
4. The number that goes above the other numbers depend on further cc values within those previously mentioned. The hiragana depends on how many people can sit in your car.
5. The amount of • (ten) or dots that you receive along with the main numbers depend on when and where the plate is issued.
6. Your city name will be displayed in kanji except for special circumstances. These include foreign dignitaries' and military vehicles, along with those that seek to go abroad with their license.

For pictures and further description, please refer to the Wiki page below.

Source:
日本のナンバープレート (Wiki)