Selvedge denim is made on old shuttle looms rather than modern high speed projectile looms. This means the fabric is woven with the weft going back and forth, so the weft threads are twisted in opposite directions. This makes the fabric tougher and more durable and gives the fabric a a clean, sturdy woven edge. Modern projectile weaving leaves a ragged, frayed edge and because the twist of the threads isn't reversed the fabric can sometimes be weaker and abrade. Selvedge denim is narrower so more yardage is required for a single pair of jeans. This makes the jeans more expensive. Modern projectile denim is 60 to 68 inches wide so a single pair can be made with less than a yard and a half of fabric while selvedge can take over three yards. And some larger size jeans will have some "piecing" in the back thigh area under the seat because the fabric is too narrow to accommodate full size pattern pieces. This piecing in larger sizes is normal and does not affect the quality of the jeans. Some Selvedge denim is also ring spun and loop dyed -again two older method that produce higher quality denim. These older processes produce denim that ages well and gets softer and fits better over time. These denims are a bit stiffer when new -much the way old fashioned jeans were back in the day. 

              
 
           Japan recently bought out much of the older looms, dyers and spinners from closed US factories to recreate this higher quality denim. Some of these machines were also bought by Indian businesses. This means that some of the very best denim is from Japan, with India following second. Japanese ring spun selvedge denim is the finest in the world and jeans made from this fabric will be more expensive, but they will also be more durable and better looking.