Most Valuable English Language Manga?

Via some Ebay research I just realized yesterday that the hardcover Lone Wolf & Cub volume 1 manga is quite probably the most valuable of all English language manga by a very wide margin. Evidently hardcover copies of Dark Horse’s first graphic novel were a limited retailer incentive and now cost as much as $300. However, 230 copies were hand-numbered and autographed by Kazuo Koike on a bookplate featuring an exclusive illustration by Goseki Kojima. Those 230 numbered copies run $1,200 to $1,300 apiece. Mine is #98. I’ve owned it for 15 years and never realized how valuable it was.