Overcome subtle dullness
You have overcome gross distractions and strong dullness, but there is a tendency to slip into stable subtle dullness. This makes the breath sensations less vivid and causes peripheral awareness to fade. Unrecognized, subtle dullness can lead you to overestimate your abilities and move on to the next Stage prematurely, which leads to concentration with dullness. You will experience only a shallow facsimile of the later Stages, and your practice will come to a dead end. To overcome subtle dullness, you must sharpen your faculties of attention and awareness.