The shell bone script for character Yin is not found, so we start the bronze script for the character,
Left is a cliff, ancient Chinese lived in caves in the bottom of cliff.
From their view, they see cliff all the time.
The right low part is cloud, the top triangle normally is a Mouth, here is Cover or Inside. Mouth covers teeth and tongue inside. A cloudy sky is similar to a big cover on earth, blocking the sunlight.
The big seal script for the character is
very similar to its bronze script.
The small seal script for character Yin,
The left is cliff, the right top is character Today, here means Cover. The bottom is character Cloud.
The clerical script for the character is
The left has changed big, but still has some similarity to the old script. The left part is called Ear Radical because it is like an ear. This one is called Left Ear Radical because it is on the left of the character. As we discussed above, it has nothing to do with ear. It is cliff, which most people including Chinese don't know that. The right top is character Today, here means Cover. The right bottom is character Cloud.
The traditional song typeface of the character Yin is
which is very similar to the clerical script.
The simplified song typeface of the character is
which is changed a lot, the right part is 月（Moon), totally different from that on old scripts.
Is this change rational? Some degree. The original scripts emphasize the Shade in the day time, the sun is blocked by clouds. The simplified song typeface uses Moon to replace the right part, which means "night with moon", different from shade in day time. But it has no sun too. Some degree rational.
Its Pinyin is Yin1.
Some of you may have heard Yin-Yang, a famous Chinese philosophy. Yin-Yang in Chinese is 阴阳, the first character is 阴. I will discuss Yang - 阳 in next post. We will see what they Yin-Yang really mean in the view of original pictography.
(Other related blogs
Creative Chinese Calligraphy - https://creativechinesecalligraphy.blogspot.com/2016/05/the-beautiy-of-creative-calligraphy-1.html)
Chinese Calligraphy History - https://leweishang.blogspot.com/2016/02/picto-calligraphy-new-way-to-write.html)