Maintaining a healthy Japanese maple will require pruning to remove deadwood and to direct growth. Although you can prune a Japanese maple lightly any time of the year, leave major pruning for the summer or winter. Don't prune your tree in the spring when the sap is rising. The best time to prune is summer; however, if you are inexperienced at pruning, it can be easier to prune in the winter when your tree is leafless. Use pruning shears for branches up to 1/2 inch thick. Use sharp saws for thicker branches.
Remove deadwood with a very sharp pair of pruning shears. You can remove deadwood at any time of year, including in the spring.
Start at the bottom of the tree and clip undesired new growth from the tree's trunk. Young Japanese maples tend to produce straight, whip like growth that isn't aesthetically pleasing.
As you work your way up the tree, prune from the inside out. Remove branches that are not at a pleasing angle. Remove branches that rub against each other or cross. Most Japanese maples look best with well separated branches that grow upwards. If two branches are crossing and one is growing toward the ground, prune the downward growing branch.
Prune away branches that grow at an angle less than 45 degrees. These branches are prone to breakage in wind or storms.