According to Wikipedia:

"Circular breathing is a technique used by players of some wind instruments to produce a continuous tone without interruption. This is accomplished by breathing in through the nose while simultaneously blowing out through the mouth using air stored in the cheeks.

It is used extensively in playing the Australian didgeridoo, the Sardinian launeddas and Egyptian arghul, as well as many traditional oboes and flutes of Asia and the Middle East. A few jazz and classical wind players also utilize some form of circular breathing.

Costa Rican saxophonist Geovanny Escalante holds the world record of almost ninety minutes for continuous playing of a wind instrument, breaking the previous record of 45 minutes held by saxophonist Kenny G."

Kenny G? Really???

Anyhow, there's more:

"The person inhales fully and begins to exhale and blow. When the lungs are nearly empty, the last volume of air is blown into the mouth, and the cheeks are inflated with this air. Then, while still blowing this last bit of air out by allowing the cheeks to deflate, the person must very quickly fill the lungs by inhaling through the nose prior to running out of the air in the mouth. If done correctly, by the time the air in the mouth is nearly exhausted the person can begin to exhale from the lungs once more, ready to repeat the process again.

Physiologically, the process is similar to drinking at a water fountain and taking a breath of air while water remains in the mouth, without raising the head from the water stream. The body "knows" to not allow water into the lungs. It is this same instinct that a circular breather uses to play their instrument.

One learning technique is to try puff out the cheeks with mouth closed using only air drawn in through the nose. This technique is very challenging, but when learned and mastered it can be repeated easily."

Does Kenny G puff his cheeks? I digress...

Enough from Wikipedia.

Actually, that's a pretty good synopsis. Also, it really helps to actually SEE what it looks like. Here's some links to YouTube videos:

The saxophonist in the video begins to circular breathe at about the :58 mark.

Here's Kenny G demonstrating circular breathing. (Yes he does puff his cheeks slightly). In spite of the plug for Rico Reeds at the end it's pretty informative.

Let's go to the Clarinet Bulletin Board which is a wonderful resource to clarinet players everywhere thanks to the efforts of the site's administrator Mark Charette (SHOUT OUT). Searching on 'circular breathing' unveiled several entries and a very infor mative article by Dr. Robert Spring. Dr. Spring's article can be printed and includes exercises. Yessss!

Off to the practice room I go.