
This post is the continuation of examining the parts of the Chinese Thread Book, the Zhen Xian Bao. Each level of expandable parts has its own characteristics. I’m going to be writing about what I call the Big Box, which is the most interior layer of the book.
On my Zhen Xian Bao Pinterest board you can see other ways people have chosen to make this layer box. Mostly what I’ve seen has not set right with me because the big box layer seems too deep. There’s no reason for this interior box to have so much volume, as it can only store a limited amount of flattish items.
Also, from what I’ve seen, the larger boxes are generally made from templates that aren’t particularly elegant. This does seem to be echoing the traditional way of making this structure, but I think something’s been lost in translation. In any case, what intrigues me most about the Zhen Xian Bao is that, at its basic level, the structure seems to ask the maker to modify each decision about the making, according to the whims of the maker and the materials that are being used.

I like using thin, strong papers to make the Chinese Thread book, but there are reasons to use a heavier paper,and heavier papers seem to beg a different way of working. Most of the images in this post show heavier paper, which are paste papers done by my friend Julie. Julie gifted me many wonderful studio supplies when she moved out of state, so I wanted to make a Zhen Xian Bao for her, using some papers decorated by her own hand. However, the tutorial video below shows the big box layer using more lightweight papers, like the ones I used in my previous post.
What I will be doing here in the written part of this post is highlighting the generalized measurements for starting the big box, then I’ll show how I’ve made some workflow modifications, which are not in the video, but which will accommodate heavier paper.

Okay, I just have to say that I absolutely loved figuring out how to determine the dimensions for the size of paper that for the big box. It took many sessions of trial and error, and I knew that I was searching for an elegant, self-referencing set of measurements, but it kept eluding me. When I discovered the secret it seemed so obvious, like why didn’t I see that immediately. So satisfying. What’s going on here is that I will be making the big box layer in the same was as the hidden box layer, with one major difference: instead of starting with a square, I start with a rectangle.
The width of the rectangle is measured by marking four widths of the hidden layer box, PLUS enough to create a middle space so that the book closes, plus a little more. You can see that space in the top photo. For the thinner papers I’m finding that 1 1/4″ extra works fine. For the thicker papers, I tacked on 1 1/2″ but the idea is to figure out how thick your book is going to be, then use this measurement plus about another 1/4″. The measurement you come up with depends entirely on what you’ve determined the depth of your finished book will be.

The height of the paper for the big box is more straight forward. Take your hidden layer box and expand it from the top and bottom. This height, plus an extra 1/4″, will be the height of the rectangle. Now construct the box according steps in the above video, then unfold everything because we need to cut away some bulk from the folded corners.

Here’s where I can’t help myself. Time to stop and admire all the beautiful geometry going on here. Snap out of it. Start snipping, but, just in case you missed this inference, this snipping only has to be done with heavier papers. The lightweight papers can stay intact.

I’ve snipped away the corner triangle, then check out the logic of the rectangle-plus-triangle snip. The fact is, the reason I’m doing it this way doesn’t become clear until it’s time to assemble the box. And it’s one of those things that is totally cumbersome to explain but obvious when you are actually doing it.

Here’s all four corners cut. I will be refolding this so it looks like I’ve cut nothing away.

Again, this part is easier to see while are doing it. Trying to explain in words would be frightening. Note the glue. It won’t go together without glue.

Here it is, reassembled. Looks just like the hidden layer box, only wider. It’s depth echoes the depth of the hidden layer box, which is also the depth the masu box, and the twist box. A perfect math for a perfect match.
I’m going to show the finishing of this book, just because I can. I chose to make the cover from a single piece of Julie’s paper. I cut the size bigger than I wanted the finished cover to be so as to leave room to turn in the edges.
After tuning in the edges I glue paper over the part of the paper that will show when the book is open.

Ta-dah!