In Koan Meditation a person is given a koan (i.e. a puzzle or a question) and he is told to keep thinking about what can be the right answer to it. Some examples of koan are:
1) How can you clap with one hand?
2) An egg of a bird was kept inside a bottle. The mouth or opening of the bottle measures exactly the size of the egg. The egg hatched inside the bottle and the little bird was fed and raised inside the bottle. Gradually the bird began to grow. Then a time came when the bird had fully grown up and had become equal to the size of the bottle. Then, without breaking the bottle and without killing the bird, how can this bird be freed? This puzzle has to be solved.
3) How can the eye see itself without a mirror (instrument)? How can the Experience (of Being) experience the Experience (of Being)?
4) Which are the questions whose answer is right if you say ‘Yes’, but is right even if you say ‘No’?
5) Who is the ear of the ear? How can the tongue taste itself?
6) How was your face before you were conceived?
7) In dreams, why don’t we see ourselves at the place where we actually are?
8) If we have attained this birth due to our karma (deeds) in our previous births, then how did we get our first birth?
9) How can effortless effort be done?
10) What is definite in deep sleep?