Chinese Radicals (5) Walking Bottom - 走之底

The big seal script for radical Walking Bottom is

The top is half of character of the following

which is an intersection of a street, meaning Walk or Street or Road.

The bottom one

 is Foot.

The two together means "walking on the road with feet".

e.g. character Advance

The top right is 隹 - Bird,  the left and bottom is the Walking Bottom, which means Advance because bird can only walk forward not backward.

As time past, the small seal script for the radical is

The top is the street/road, changed a lot, but it is still like the road. The bottom is the foot, which is right below the top part.

The character Advance becomes

The right part is Bird.

The clerical script for the radical is

The top is the road/street, not much similarity to the old radicals. The bottom big horizontal stroke is the extending foot.

The character Advance of clerical script at first became

There are three very short strokes which is the simplified street/road, but bottom is the modified foot to get the typical clerical long Insect-head-bird-tail stroke.

The clerical script of the radical continued to evolve to become to the following

The radical on the left is simplified to connected two bottom short strokes, which is the final or current form of Radical Walking Bottom.

The Radical Walking Bottom means "walking on the road with feet".

Chinese Radicals (4) Four Drops - 四点水

The Four Drops radical is four dots on the bottom of a character.

Four Drops radical is from

1, the part of animal

Let us see character of Fish

From left to right: shell bone, small seal, and clerical script.

We see that the clerical script of Fish has four dots on the bottom,

is called Four Drops radical, which is from the tail of the fish.

Let us see character of Horse

From left to right: shell bone, small seal, and clerical script. 

The clerical script has four dots, which are from the legs of horse.

Let us see the character of Bird

similarly, the four dots in the clerical script are from the claws of the bird.

2, Fire

Let us see the character of Burnt

From the left to right: shell bone, small seal, and clerical script

The top is a bird, and the bottom is Fire, which becomes to four dots in clerical script.

Let us see character of Black

From left to right: big seal, small seal, and clerical. The top ones are faces with black dots, and the bottom are Fire. In clerical script, the Fire is four dots. 

Conclusion:

The four dots are either the tail or legs of animal in the first group, or the Fire in the second group. 

However, in the simplified characters of Fish, Horse, and Bird, the Four Drops become one line

The Four Drops radicals from the Fire keep in four dots.

Chinese Radicals (3) Three drops - 三点水

The shell bone script, big seal and small seal script for Three drops are just character Water

or 

for example,

or

The left is Liquor, the right is Oil, both are small seal script. Both have Water character on the left.

So there is no Three drop radical or Three drop radial is same as Water character in shell bone, big seal, and small seal script.

When clerical script was used, people wrote Water like the following,

But people had never used it as side radical in character, instead people first tried to turn the small seal script Water to horizontal

The character became like 

which has problem: is it one character or two?

Therefore, people simplified the left horizontal Water to 

which is narrowed the Water, so people could write Oil as

It could be put in a square of the same size with any other characters, people are sure that it is one character, not two.

Because it is so different from the character Water, so people call it Radical Water, which is really from character Water. The three drops standard script, song typeface later on have the similar form.

Chinese Radicals (2) Rice Crop - 禾字旁

Rice Crop or Grain radical comes from character Rice Crop - 禾字旁

The big seal script for Rice Crop is

The big seal script for Fire is

If we put the above big seal Rice Crop and Fire together

which is Autumn or Fall. Each character is independent.

The small seal script for character Rice Crop is

The small seal script for character Fire is

We put small seal script Rice Crop and Fire together,

Which is Autumn or Fall. Each keeps its own form.

The clerical script of Rice Crop is

The clerical script of Fire is

If we put them together, we got

Two strokes are across to each other. If we exchange the positions of the two characters, put the Fire on the left, and the Rice Crop on the right, we would have the same problem: two strokes are across each other.

In order to avoid the problem, ancient people drew the right-falling stroke of left character shorter to give room for the left-falling stroke of right character. We could have

Then we have the left as

Which is called Rice Crop or Grain Radical.

Later, standard script, and song typeface Wood have the similar radical.

Now we know that the Rice Crop radical actually is Rice Crop character. There were no Rice Crop radical before clerical script because the two characters could keep their original forms. It is changed to avoid the across of the two strokes in late clerical, standard scripts, and song typeface.

Chinese Radicals (1) Wood Radical - 木字旁

Wood radical comes from character Wood - 木字旁

The original shell bone script for Wood is

If we put two shell bone Woods together

which is Forest of shell bone script. Here the two Wood are equal.

The small seal script for Wood is

We put two small seal script Woods together,

which is the Forest of small seal script. The two Wood are equal too.

So far so good.

The clerical script of Wood is

The difference from the clerical script is the left-falling and right-falling strokes are outward or stretch out, not inward like the old scripts. Because clerical script was popular in Han Dynasty when people could make papers, so people could draw the strokes horizontally very wide. In contrast, people could only drew shell bone script and small seal script on bamboo slips in the earlier time, so the strokes of characters are inward.

If we put two clerical script Woods together, we got

People faced a problem, two strokes are across each other which is not acceptable. So people drew the right-falling stroke of left Wood shorter to allow the left-falling stroke of right Wood to have room to stretch out. It becomes like the following

The left part 

is called Wood radical because it is different from Wood character but actually it is from Wood and means Wood. Wood radical is only on the left of the character, because it is a rule that when the across happens, the left part should give space for the right part. The above 林 has the right part keeping no change from 木 character.

Later, standard script, and song typeface Wood have the similar radical.

So we know now that the Wood radical is actually from the Wood character. There were no Wood radical before clerical script. It is changed to avoid the across of the two strokes in late clerical, standard scripts, and song typeface.