A common question I get is whether drawing a line on the golf ball helps align the ball down the intended target line when putting. The line is generally marked using a sharpie or is often already imprinted on the ball. There are several variations from which to choose: a single line, a double line, a triple line, a cross, an arrow, and so on. The line is primarily used to help align your putter at address on the intended target line.
An additional benefit from the line would be the ability to check and see how you are rolling your putts. If the line rolls end over end, it indicates true roll. If it wiggles to the left or right, you might want to check your putter face at impact, path direction or putt stroke mechanics.
Although a line on the golf ball may assist you in lining up to the target line as well as help create consistency in your setup routine, there are studies which indicate this method can negatively impact your initial aim. The golf ball is a round sphere and therefore can cause an optical illusion toward the inside of the target line.
I work with a lot of golfers from high handicappers to professionals and have observed good and bad results from using a line. Some of my students benefit from the line by improving their aim and routine but some perform worse when some type of line on the ball is used.
The best way to see if this is something that might work for you is to draw a line on a few golf balls and roll some putts. You can then determine whether your results get better, worse or stay the same.
Call me to schedule a lesson so I can you help find the putting routine that yields the best results for you.