First developed on the Star Destroyer Tsunami, the Tsunami Sequence is an extremely difficult maneuver to pull off because it requires precise, to the second timing and unhesitating perfection in reflexes and accuracy. Because of the difficulty of the Tsunami Sequence and the ever-changing battlefield conditions, there has to be a likewise perfection in the cooperation of gunner and computer - to combine the two, as much as possible, into a cohesive whole.
In essence, the Tsunami Sequence calls for a Star Destroyer’s turbolasers to concentrate their fire at a single point on the enemy’s shields in a combined, destructive wave. A split-second later, as the enemy shields shift power to strengthen the area being hit, a second wave slams in just on the edge of the first wave, burning away at the weakened shields and doing more damage than the first wave because the shields don’t have time to readjust.
The sequence continues along those lines, as wave upon wave strikes weaker and weaker areas on the enemy shields. In essence, it redirects shield energy away from where the Star Destroyer's guns will hit next. If done right, the Tsunami Sequence can be extremely effective, bringing down enemy shields in half the time it normally requires and is nearly impossible to defend against.
The only thing that keeps the Tsunami Sequence from being standard practice is its difficulty for crews to pull off effectively.