Sharing fishing methods, skills and experiences, most of which are accumulated in decades of fishing career.
After decades of using ultrashort sub-lines, I have said the following experiences. Touch the bottom with an ultrashort sub-line, especially with a splay ring or a plumb.
Flat fishing has no hook for one and a half eyes, and the eight-character ring touches the bottom, with a long line of 5 cm and a short line of 2 cm. You don't need a splay ring, use a vice tong. As long as the hook floats up and down, the fish will flow slightly, which is better for catching crucian carp. The main line 1.5-2.0 sub-line, with zero 1 clear water, is slightly stronger than the big drift, and the running water is soft for fishing.