This is Castlevania for the Sharp X68000, a Japanese game disk set.
The set includes the game disk, manual, and box. The disk has been tested — the title screen was confirmed to display — and comes with its original label and sleeve. The manual is original; as shown in the photos, its staple has rusted. The box is original.
Mold that had formed on the floppy disk has been removed, but there's a chance the game may not work properly on your X68000 depending on its condition.
