The first story is from Thomas Cleary's introduction to Sun Tzu's The Art of War. The second is from Zen Flesh, Zen Bones. The third is from Moss Roberts' Chinese Fairy Tales and Fantasies.
Jean Giono's The Man Who Planted Trees is too long for this webpage, but a PDF of it can be found at http://www.ftpf.org/The_Man_Who_Planted_Trees.pdf
According to an old story, a lord of ancient China once asked his physician, a member of a family of healers, which of them was the most skilled in the art.
The physician, whose reputation was such that his name became synonymous with medical science in China, replied, "My eldest brother sees the spirit of sickness and removes it before it takes shape, so his name does not get out of the house. My elder brother cures sickness when it is still extremely minute, so his name does not get out of the neighborhood. As for me, I puncture veins, prescribe potions, and massage skin, so from time to time my name gets out and is heard among the lords."
The Zen master Hakuin was praised by his neighbors as one living a pure life. A beautiful Japanese girl whose parents owned a food store lived near him. Suddenly, without any warning, her parents discovered that she was with child. This made her parents angry. She would not confess who the man was, but after much harassment at last named Hakuin.
In great anger the parents went to the master. "Is that so?" was all he would say.
After the child was born it was brought to Hakuin. By this time he had lost his reputation, which did not trouble him, but he took very good care of the child. He obtained milk from his neighbors and everything else the little one needed.
A year later the girl-mother could stand it no longer. She told her parents the truth -- that the real father of the child was a young man who worked in the fishmarket. The mother and father of the girl at once went to Hakuin to ask his forgiveness, to apologize at length, and to get the child back again.
Hakuin was willing. In yielding the child, all he said was: "Is that so?"
A man who lived on the northern frontier of China was skilled in interpreting events. One day for no reason, his horse ran away to the nomads across the border. Everyone tried to console him, but his father said, "What makes you so sure this isn't a blessing?"
Some months later his horse returned, bringing a splendid nomad stallion. Everyone congratulated him, but his father said, "What makes you so sure this isn't a disaster?"
Their household was richer by a fine horse, which the son loved to ride. One day he fell and broke his hip. Everyone tried to console him, but his father said, "What makes you so sure this isn't a blessing?"
A year later the nomads came in force across the border, and every able-bodied man took his bow and went into battle. The Chinese frontiersmen lost nine of every ten men. Only because the son was lame did father and son survive to take care of each other. Truly, blessing turns to disaster, and disaster to blessing: the changes have no end, nor can the mystery be fathomed.