The J is a great correction stroke to keep you going straight. Paddling longer distances, smoothly and with less effort, is easiest with the J stroke correction because the same face of the blade works throughout the forward stroke and correction. The J stroke is much smoother and ultimately faster than a rudder, or stern pry: but it has its limitations. The J is not very good for starting from a standstill, or for making sharp corrections, or for ferrying.
The J is a great correction stroke to keep you going straight. Paddling longer distances, smoothly and with less effort, is easiest with the J stroke correction because the same face of the blade works throughout the forward stroke and correction. The J stroke is much smoother and ultimately faster than a rudder, or stern pry: but it has its limitations. The J is not very good for starting from a standstill, or for making sharp corrections, or for ferrying.
In the J stroke, the top thumb of the T grip hand twists forward and down thus the power face of the blade works throughout the stroke. To learn the J, get your speed going with forward stroke and a pry correction, switch to the J, and try to go in circles towards your paddling side. When you have that mastered, increase the radius of your circles until you can go straight. Expect some difficulties tripping over the J until you get a feel for getting the J to catch.
To accelerate from a standstill it is often easiest to aim the boat towards your paddling side to avoid corrections on the first few strokes. Remember, the rudder/pry is often easier than a “J” for starting and for many moves on whitewater.
As you develop some experience and learn this basic stroke, you will be able to anticipate the boat turn, and correct before the boat really starts to spin. Don’t waste energy trying to correct with stronger forward strokes.