What we do know, is that before grade 0 there was an original Vanguard. This is different from the Cardfight!! Vanguard we are now long acquainted with. It's also something of an open secret--the only public information on it reached fans by way of an art piece dated 2010 taken from AnimeNation, who sourced their information to Anime News Network, who sourced theirs to Gigazine, while neither of the latter two websites featured the image.
In this early stage of development, Kamui is missing from the storyline, and as such the Nova Grappler clan is not featured. Certain design choices in this artwork suggest that Kamui was a very late addition to Vanguard's storyline, which is unfortunate but supported by the general disconnect between him and most of the series' plot. To get to that point, we first need to look at another contemporary example of the old Vanguard, an even less reported on event from the Tokyo Toy Show 2010;
On the left we can see Stardust Trumpeter, Blaster Blade, Dragon Dancer Monica and Dragonic Overlord. The card borders are significantly different at this point. For example, shield scores are still tallied on the card's left side, but they're aligned more closely to the bottom, and Monica lacks a trigger icon. For all we can tell, triggers do not exist at this stage. On another note, look closely at the upper left hand corner of each card--boost, intercept and twin drive icons are missing, and in fact Monica is listed as a grade 1. It appears that this skill system, and the existence of trigger units at all, was not added until later.
Now let's look at the event's commemoration item;
TV anime 2011!!"This is probably the single rarest Vanguard card in existence, seeing as the subject of this photo is the only one we know of. It's also early artwork--really early. You can tell this by the design of Blaster Blade's sword, which is a non-segmenting, more traditional longsword with a type of fanged hilt rather than the laser-shooting monstrosity we're familiar with. The old design fits in with how Blade's skill was initially depicted in the manga, as a second attack made on a rearguard unit. We can also see clearly from this card that the old borders did not have a critical rating--tying into the "no triggers" theory--but an n* after the power. Given how it's used in mathematical notation, perhaps n* was some time of multiplier that triggers eventually replaced?
This is not the only artwork to draw Blaster Blade as such. There was some minor dispute over how Blade was depicted in Alfred Early's artwork, and Early's name may in fact be an in-joke on the original Vanguard;
From this we can draw some conclusions about the sequence of events in Vanguard's development;
- At the earliest stages, Blaster Blade and his sword are designed. At the same time, Alfred's initial artwork is laid out and eventually completed, as is early planning for the manga. The first card border is drafted and used in the event cards.
- Ito begins work on the first chapter of the manga.
- The event cards are printed.
- Blaster Blade's sword is redesigned to accommodate for his pinpoint buster skill being changed to a beam.
- The poster-sized cards are printed.
- The initial poster this article presented is made.
- Kamui is added to the storyline.
- The second card border is drafted and finalized. At the same time, trigger units and grade 0 is implemented into the game.
- Due to the art, Alfred is reinvisioned as Alfred Early while a new Alfred is drafted to be the King of Knights.