The sign underneath the gate says "Tian Xia Wei Gong" - a phrase used by Dr. Sun Yat Sen to say that everything in the world belongs to all people, rather than just to the Emperor. It indicates that at the time of the gate's building Chinatown was under the influence of the Republic of China (Taiwan) more than that of the People's Republic of China. This changed in a few years when relationships with PRC were normalized under the Nixon administration. You can see which country is in accendance today by noting the ratio of PRC vs Taiwanese flags on the buildings. The signs over the side gates urge you to filial piety, respect, love, and peace. The fish atop the gate symbolize prosperity, while the dragons symbolize power and fertility, and the ball between the dragons symbolizes Earth. Underneath the gate are two Fu lions. The lioness at right rests her paw on a cub, to symbolize the safeguarding of the people, while her mate at left has a pearl, symbolizing protection of the gate and, by extension, the neighborhood behind it. These lions, as well as the tiles and the roofing, were gifted to San Francisco in 1969 by the government of Taiwan.