I have been reading "The Zen Koan" by Isshu Miura and Ruth Fuller. Various other books also mention them and stress their importance, such as "Discourse on the Inexhaustable Lamp", I have also heard them referred to in Zen Gateway podcasts and articles. So they appear to be very important for the training, but seem to need testing face to face with the teacher in a formal temple training setting. Is there a way that they could be part of the practice at home?

For insight meditation certain schools use the breath at the nose others use the breath at the abdomen as it allows greater awareness of the body so not reducing peripheral awareness as much as when focussing on the breath at the nose. Comments?