What is an OBI strip, and does it affect CD value?
The short answer: yes, enormously. A missing OBI can take most of the value off an otherwise mint Japanese CD.
What it is
The OBI (帯, 'sash') is the narrow printed paper band wrapped around the spine side of a Japanese CD case. It carries the Japanese title, the catalogue number, the original retail price, and often promotional copy about bonus tracks or the pressing.
It is not packaging in the disposable sense — collectors treat it as part of the release.
Why it moves the price so much
OBIs were designed to be thrown away by the first owner, so surviving examples are far scarcer than the CDs themselves. The strip is also the quickest way to identify exactly which pressing you have, because the catalogue number and price code are printed on it.
As a rough rule, a Japanese CD without its OBI trades much closer to the price of a standard used copy, while a complete copy holds the collector premium.
Spotting a replacement or reproduction
Reproductions exist. Check paper weight and colour (originals are usually slightly warm, not bright white), print sharpness at small type sizes, correct fold creases from being wrapped, and whether the price code matches the era of the release. An OBI whose catalogue number disagrees with the disc or the rear insert belongs to a different pressing.
How we list them
Every Japanese pressing on SideOne states whether the OBI is present, whether it's original to the copy, and any tears or fading. If it isn't mentioned as present, assume it isn't there — and the price reflects that.