The Mobile Suit Variations (モビルスーツバリエーション), simply known as MSV to fans, are variations on the mechanical designs seen in the anime Mobile Suit Gundam; specifically those of the Universal Century during a period known as the One Year War. These mobile suit variations are official designs, and included detailed histories and in many cases even have detailed backstories given for their pilots. Some were meant for a cancelled original series in 1983, and a few were even originally intended to appear in Mobile Suit Gundam, but their appearances were cut due to storyline alterations. While never seen in their own animation series, most of the MS models (as well as the backstories and pilots created for them) are considered canonical, and a few were later seen in other side-stories, manga, or video games. In a few cases, MSV designs even made brief appearances in Zeta Gundam and Mobile Suit Gundam ZZ.
The MSV concept would be repeated on a more limited scale for Zeta Gundam, Gundam ZZ, Char's Counterattack, Gundam F91, and Victory Gundam, with both the number of designs and the detail of their backstories significantly reduced. In addition, "Kunio Okawara's MS Collection", known to fans as "M-MSV" (Missing-Mobile Suit Variations), is similar to the MSV concept but spans from the One Year War through the Gryps Conflict. It was not until Gundam SEED's MSV series (the first for an Alternate Universe series) that the original MSV formula, with detailed backstories and pilots, was duplicated.