Bodhidharma leaving for china What prompted the great BodhiDharma to go to China to spread his teachings- why not at home in the first place. Was he the founder of kalari payattu which has become somewhat unknown to us?
This is a long-standing mystery, described in many Zen Koans.  Here are two Koans from the Gateless Gate that mentions it:

Kyogen said: &quot;Zen is like a man hanging in a tree by his teeth over a precipice. His hands grasp no branch, his feet rest on no limb, and under the three another person asks him: `Why does Bodhidharma come to China from India?' If the man in tree does not answer, he fails; and if he does answer, he falls and loses his life. Now what shall he do?&quot;
A monk asked Joshu, &quot;With what intention did Bodhidharma come to China?&quot; Joshu answered, &quot;The oak tree in the front garden.&quot;

And here are three Koans from the Blue Cliff Record that mention it:

A monk asked Kyorin, “What is the meaning of the Patriarch’s coming from the West?” Kyorin said, “I am tired from sitting for a long time.”
Ryuge asked Suibi, “What is the meaning of the Patriarch’s coming from the west?” Suibi said, “Bring me a chin rest.” Ryuge brought one and gave it to him. Suibi took it and hit him. Ryuge said, “You may hit me as you like. After all there is no meaning to the Patriarch’s coming from the west.” Ryuge also asked Rinzai, “What is the meaning of the Patriarch’s coming from the west?” Rinzai said, “Bring me a sitting cushion.” Ryuge got one and gave it to Rinzai. Rinzai took it and hit him. Ryuge said, “You may hit me as you like. After all there is no meaning to the Patriarch’s coming from the west.”
A monk asked Great Master Ba, “Apart from the Four Phrases, beyond one hundred Negations, please tell me directly, Master, the meaning of Bodhidharma’s coming from the West.” Master Ba said, “I am tired today, I can’t explain it to you. Go and ask Chizo.” The monk asked Chizo about it. Chizo said, “Why don’t you ask our master?” The monk said, “He told me to ask you.” Chizo said, “I have a headache today, I can’t explain it to you. Go and ask Brother Kai.” The monk asked Brother Kai about it. Kai said, “I don’t understand nothing about that question.” The monk told Great Master Ba about it. Great Master said, “Chizo’s head is white, Kai’s head is black.”