Use the straight stitch needle plate for straight stitching in the center position. The smaller opening is great for working on fine fabrics that are prone to getting pulled into the feed dogs or the larger hole in the zig-zag needle plate.  For even better results use with the Straight Stitch presser foot.

For Janome 7mm machines including the:  4300QDC, 5300QDC, Sewist 740DC, Sewist 780DC, and Skyline S3.