I have been hunting around the internet for a good tutorial on the Japanese x and + block finishing at 12.5 inches. Much to my dismay, I could not find one. I decided to backwards engineer it and I thought I would share what I came up with!
Here is my final block, finishing at 13 x 13 (12.5 x 12.5 once it is sewn to its neighbor blocks)
My pictures came out like I was using a fish eye lens...weird. Anyway, this is the first cut I have made into my Good Folks and man was it nerve wracking.
So after some careful math, I figured out that you need:
(8) 3 inch squares for the triangle pieces (blue in my block)
(4) 3 inch squares for the ends of the plus (yellow in my block)
(2) 3 inch squares for the plus (red diamonds)
(1) 8 x 3 inch rectangle for the plus (red diamonds)
(4) 5.5 inch squares for the x pieces (I chose 4 different prints to make it scrappy)
I started by piecing the x part of the block. Each 5.5 inch square will get (2) 3 inch squares sewn into opposite corners like this. I sewed a vertical seam from the top corner of each blue square to the bottom of each.
Next, iron the squares back onto themselves (wrong sides together) and cut away the excess fabric like so
Next, I sewed together the pieces of the plus part of the block using a 1/4 inch seam. I ironed my seams open mainly because I prefer the look. You can press them to the side as well.
After that, I sewed 2 of my 5.5 inch squares to each of the shorter plus pieces. This is where you have to get careful about placement. You want to make sure the 'points' of your x pieces are pointing towards your main plus color. In mine, I made sure my x pieces were pointing to the red diamonds, as opposed to the yellow.
Finally, I sewed each of those pieces to the final portion of the + part of the block.
I really like the scrappy look of it! It was a super easy block with some very fast piecing. I have seen people use color and fabric in numerous ways for this block, but I find the scrappy ones to be the most interesting and striking.