Chapter V. Aircraft Insignia
Article 22
Pertinent to the provisions of Article 12 of the Act, an aircraft after being registered shall display on a conspicuous spot the nationality emblem of the Republic of China and its registration number (hereinafter referred as markings).
The nationality emblem of Republic of China’s civil aircraft shall be represented by the English letter “B” followed by a 5-digit Arabic numbers aligned left to right in the order shown below：
1) nationality emblem followed by a dash.
2) registration number follows the dash.
An aircraft after completing nationality registration will not have its markings altered, except in the case registration has been revoked and application for new nationality registration becomes necessary.
http://209.85.129.132/search?q=cache:fQPK71J8NrkJ:www.caa.go...
A national emblem symbolically represents a nation. Most national emblems originate in the natural world, such as animals or birds, but another object may serve.
National emblems may appear on many things such as the national flag, coat of arms, or other patriotic materials. One should not confuse a formal national emblem with less formal symbols perhaps associated with tourism or clichés, for example windmills in the Netherlands. Many unofficial symbols are as or even more important than the official ones. However official symbols are defined by law, which guarantees the proper use of them.
http://en.wikipedia.org/wiki/National_emblem