Shodo (書道) - Thư Đạo in Vietnamese - means artistic calligraphy or devine drawing.
In Shodo Taichi we perform the drawing of the Yin-Yang Logo through hand movements.
Yin-Yang Logo can be drawn in one of the following two forms:

and

In the simplified form, these two logos become:

and

Placing one on top of the other, we get the following picture. Note that the picture actually has two circles and one mathematical infinity symbol:

Rotating the picture 90 degrees, we get the following picture:

It is this picture that we draw with our hands in Shodo Taichi. The hands are open and the palms are facing each other. Holding a ball will help keep the hands in place.
The following steps are performed in order:

1. Draw the surounding circle
2. Draw the infinity symbol.
3. Draw the surounding circle again

These 3 drawings form a building block of Shodo Taichi. With a close look, we will see that it actually has 2 distinctive components: a circle and an infinity symbol. The second circle is just a repetition of the first one.
With only these 2 components, Shodo Taichi is therefore the simplest Taichi style that ever existed.

There are 2 major hand movements in Shodo Taichi:

1. The Circle.
2. The Mathematic Infinity Symbol (aka Figure Eight).

Each of these major hand movements has 2 versions

1. The Horizontal (aka the Low).
2. The Vertical (aka the High).

Shodo Taichi therefore have four distinctive hand movements:

1. Circle Low.
2. Circle High.
3. Infinity Low.
4. Infinity High.

Follows are the graphical descriptions of these hand movements:

Circle Low

Circle High

Infinity Low

Infinity High