Ryujin 3.5 (Satoshi Kamiya)

The "3.5" version of the Ryujin includes an entirely newly designed, fully articulated spine and dramatically denser scale work than the earlier 1.0 and 2.0 versions. The systematic folding of these thousands of scales is the most time-consuming part of the process.

To achieve the proper density of scales, the Ryujin 3.5 requires a massive single square of paper, usually measuring at least 1 meter by 1 meter. Despite the massive starting size, the finished model is often less than a foot long due to the hundreds of overlapping layers.

The Ryujin 3.5 is generally considered by the origami community to be significantly harder and more tedious to fold than the Ancient Dragon. This is due to the use of a specialized technique to individually wrap hundreds of scales on the dragon's back, legs, and tail.

While Satoshi Kamiya designed the Ryujin 3.5, master folder and mathematician Robert Lang helped heavily analyze and diagram its complex crease patterns. Lang's structural work on the underlying grid helped make the model highly systematic to fold.