Couching is one of the simplest of stitches to master, yet can be one of the most sophisticated forms of embroidery. It is a good first stitch for a child, yet the most suitable for working with gold and other fragile metal threads. And gold work, as you may know, is probably the most difficult form of embroidery - the sign that you've really arrived.

A close cousin of back stitch, couching is simply a means of sewing thread to the surface of your material, using a single back stitch at right angles to the direction of the main thread. But within this basic frame work you can create so many variations with the couched thread or the stitches themselves that you'd barely recognize them as the same stitch.

You can allow the couched thread to wander free over your background linen to form an open effect, or use it to fill an area of any shape, or as an outline or even in a circle. You can do raised work with felt or string, or choose couched threads in contrasting colors, or do gold work with a similar color thread to create the effect of gold fabric stitched onto your linen.

It's not surprising that the most appropriate stitch for gold work would have a regal history itself. In the 13th century, the English couched gold thread on ecclesiastic vestments, the theory being that God's house deserved the very best that man could produce. These church vestments, called Opus Anglicanum , or English Work, were stitched in Couche Rentre (Pulled Couching), a means of covering a background linen completely and couching the gold thread in such a way that it appeared to be going through the fabric itself. The result was similar to bargello, but worked in solid gold.

A more recent example of the versatility of couching appeared at a special exhibit of Russian clothing at the New York Metropolitan Museum of Art last year. One of the most magnificent exhibits was Queen Sofia's wedding dress, made in the latter part of the 18th century. The gown was of silk fabric brocaded with silver thread in a variety of stitches, and with the tiniest of pleats sewn down (a technique called rushing) for a ruffled effect. Through the years, the dress had naturally begun to disintegrate. So, to restore it, the Russians took it all apart, laid it into an embroidery frame and couched near invisible parallel lines of fine silk thread onto the fabric, thereby strengthening it for posterity.

If you've never worked in couching, it's best to start with the basics - the more pliable and well-behaved wools - before you venture into gold work, and with the simplest form, which is random couching. Either one or two threads may be used in your needle, and any number of threads may be couched down, but for all forms of couching, a frame is essential.

Simply lay down a bundle of threads, and with your threaded needle, come up through your fabric, over your threads and down in almost the same hole. Repeat, keeping your stitches at right angles and at regular intervals as you sew down the thread in a meandering line. When the line is completed, thread the couched thread through a large-eyed needle, plunge it through the material exactly in the hole made by your last stitch and cut it off short (about 1/4 inch) on the reverse side.

The same principle holds true for couching to fill a shape, but you simply work a straight line and, at the end of the space, reverse the direction of your thread. And for couching in a circle, draw a guide on your fabric (lightly in pencil) of regularly spaced lines radiating out from the center. Work your couched threads round and round in widening rings, placing a couching stitch on each pencil line.

Once you've mastered the technique, you can begin to get fancy with your stitches. When working in rows, you could "brick" (see illustration) your stitches by spacing them alternately to make a regular pattern, or arrange them in a "mile fleur" design - little groups of four stitches that resemble tiny flowers. And how about puffy couching, formed by lifting the couched threads with your needle after you take each stitch - great for flowers or a prancing horse's tail!

All the basic couching stitches may be worked in gold, as long as your follow a few basic pointers: Always use silk or mercerized cotton thread for couching down the gold, and always strengthen the thread by waxing it with beeswax (available at most sewing stores) two or three times. Have a huge dagger of a needle (No. 18 chenille shape or No. 18 needlepoint) on hand to open a hole in your background material and "plunge" your threads to protect them as they are pulled through to the back. Always couch a pair of threads, since a single thread would require too many stitches and move than two would bunch.

If you really want to test your ability as a needleworker, you might try Italian Shading, the most advanced form of couching gold work (and the only one that doesn't require waxed thread). One method is to vary both the colors and density of your couching stitches to shade an area of your design. The other is to lay your gold threads in straight rows and create a desing or pattern in different colors of thread, in which case the gold acts as an appropriate and dazzling backdrop for your master work!