I Ching (Yi Jing 易经) is the very foundation of
Daoism and Chinese culture. But I Ching that
we normally refer to is just one third of all
I Ching that were created by the ancient
Chinese.
This one third of I Ching we
know today is actually called "Zhou Yi
(Change in Heaven 周易)", meaning:
"the I Ching compiled during the Zhou
Dynasty" (1100 BC – 221 BC). It
consists of three key parts: concepts (li
理), charts (xiang 象) and numbers (shu 数), and illustrates three
fundamental tenets: transcendence of all
things (bianyi 变易), simplicity of
underlying principles (jianyi 简易) and eternality of
unblemished Dao (buyi 不易).
The other two I Chings are
Lianshan (Link to Mountain 连山) and Guicang (Save in
Earth 归藏), both were
evidently compiled before that of Zhou Yi.
Unlike Zhou Yi that starts
with the hexagram of Heaven, in Lianshan the
first hexagram is Mountain, and in Guicang it
is the Earth hexagram that tops the rank.
While Zhou Yi is believed to
be compiled by Duke
Zhou
and Lianshan is allegedly created by Red
Emperor - who was a thousand-year older than
Zhou - Guicang is said to have an even more
venerable author: the Yellow
Emperor himself.

There are purported original
text of Lianshan and Guicang in Books
Discovered in Three Ancient Tombs (Gusanfen
Shu 古三坟书) and Lost
Classics Recovered by Yuhanshan Studio (Yuhanshanfang
Yishu 玉函山房辑佚书), but both
are considered fake by most experts.
In March 1993, large amount of
fragmented bamboo books were unearthed from a
tomb dating back to the Qin Dynasty (221 BC
– 207 BC). It contains over 4000 characters
and more than 70 charts on the topic of
Guicang. However, a readable version of any
page is yet to be reconstructed.
Three I Chings, apparently,
contemplate the universe from slightly
different angles. Zhou Yi places its emphasis
on Heaven, Guicang views the world from the
perspective of Earth, while Lianshan focuses
on Mountain, the linkage between Heaven and
Earth.