Is the substance of space the "Chi" that Chinese sages referred to?

Put simply, chi (qi) is that which gives life. In terms of the body, chi is that which differentiates a corpse from a live human being.

The word you're probably talking about is spelled "qi" in pinyin and "ch'i" (note the apostrophe) in Wade-Giles. It's never spelled "chi" in any romanization system for Chinese. "Chi" and "ch'i" are different syllables with different pronunciations.

“修身齊家治國平天下” said by a Chinese ancient sage
Wade-Gilos:
hsiu shen ch'i chia chih kuo p'ing t'ien hsia
Pinyin :
xiu　shen　 qi　jia　zhi　guo　ping　tian　xia
Which means one must behave well before a harmony family can be achieved; Then, He/her has a chance to govern the country properly, and lastly pacify the world.

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