This is a post about the Tokyo Subway Map Quilt-Along, which you can join at any time.
The "X"s on the pattern indicate the placement of the colored solid fabrics. If you follow my prints vs. solids layout, including the proportion of prints to solids I listed in the cutting instructions, you'll end up with prints and solids evenly distributed across the quilt top and one solid square of each different-colored line in each block through which that line passes.
I noticed, as I was cutting my fabrics, that some of my sets of squares included a rather wide range of value (lightness or darkness). Because the piecing layout is all about lines running around the quilt, I'm going to pay attention to that when I'm placing the squares in each block. If you look closely at the way I arranged my gray squares above, you can see that the ones on the left side are lighter. I intentionally put the light squares together and the dark squares together. My hope is that, if I continue to do this in each block, it will give a look of flow and movement in the finished quilt.
Once you're happy with your arrangement, stack each row of squares, from left to right, with the top square in each stack being the one that was formerly on the far left and the bottom square being the one that was formerly on the far right. Keep the stacks of squares in the same arrangement of 8 rows, so that you can easily identify their proper order.
Working from the bottom or the top (it doesn't matter which -- just keep track of which is which) piece each row of squares together. Rather than chain piecing, which I find can easily confuse the order, I suggest starting with the top (left-most) square in the stack and sewing the next square to its right side. Repeat, sewing each square to the right side of the previous square, until you have the whole row sewn together.
As long as you're carefully lining up the squares as you go, there should be no need for pins or to stop and press between seams. Just focus on keeping the squares lined up and your seam allowance consistent. If you have a seam guide (like the one I'm using in the above photo) or a 1/4 inch foot, you may find it useful here. Low-tech solutions like putting a strip of blue painter's tape on your machine can also be helpful.
There's no getting around the fact that these little squares can be kind of fussy to piece. Accurate piecing is going to be important to the look of your finished quilt, but please don't go crazy trying to perfect everything. The two things to focus on here are sewing straight seams and using a consistent seam allowance. For this project, it is not essential that your seam allowance be a perfect 1/4 inch. You just need to keep it the same throughout the project. If following the edge of your 3/8" wide foot is easiest, by all means do that! It will mean that your finished top is a few inches smaller, but will probably save you a lot of headache.
If you're having trouble with your squares separating, it may mean that you're using a too-long stitch length. I had mine set at 2 and found that worked fine. Your machine may have a different scale, so play around with some scraps to determine what you think will work best for you.
Pin the fourth and fifth rows (the two rows at the center of the block) together, matching seam allowances. When I piece identical rows like this, I like to start by matching up the center and pinning outward to each side. Since these squares are so little, I used a single pin to secure all of the seam allowances between each square.
Use more pins, if it makes you more comfortable, but don't stretch or warp your work to make things match. Remember that, when you join these two pieced rows, making a straight seam will be your goal. It's inevitable that, somewhere in your quilt, there will be something a bit "off." Don't let it get you down. Just be a little strategic. For instance, in this block, matching the pieces of that red line is more of a priority than making each and every white square match.
Continue adding rows to the top and bottom of the two you've just joined, until all rows are joined, pressing seams open. Unlike when we were sewing the squares into rows, it's fairly important to stop and press each longer seam before moving on to the next, as this will allow you to see how things are lining up and make little adjustments, if necessary.
Square up the sides of your block, but be careful not to take off too much. I like to measure out from the nearest seam allowance, which is easy to do with this gridded block. If you're using 2" squares and a 1/4" seam allowance, your cutting line should measure 1 3/4" out from the seam allowance nearest each edge.
A finished block made with 2" squares and a 1/4" seam allowance should theoretically measure 12 1/2" x 12 1/2". However, as I mentioned above, in this project having straight, consistent, seams is far more important than hitting that exact number.