Getting to an angle and breaking posture: The front triangle will always be the most important of the five main varieties of triangle in the sport of Jiu-Jitsu due to the disproportionate amount of time spent on guard scenarios relative to other grappling arts.
When using the front triangle from bottom position, the two biggest concerns are getting advantageous ANGLE and breaking your opponents POSTURE. The problem is that your opponent usually knows this and thus will do everything he can to prevent you doing this. It is very good therefore, to have a sound mechanical means of getting angle and KEEPING ANGLE AGAINST RESISTANCE.
One of the very best methods is a scoop grip under your opponents leg to pull yourself around perpendicular to your opponent. Unfortunately this grip is not always possible due to an opponent’s positioning. An excellent substitute is to under the arm on the same side as your unsuccessful scoop grip attempt on the leg. This has the added benefit of keeping your opponents head broken down in poor posture.
Here, Garry Tonon applies a particularly tight reinforced variation to lock in an extremely tight triangle finish on outstanding American grappler Javi Vazquez. Once a triangle is locked on in this fashion escape becomes extremely difficult. Once you lock your opponent head and arm inside your legs - remember - ANGLE AND NEGATION OF POSTURE ARE YOUR TWO MAIN CONCERNS. Focus on them and watch your finishing rate go up!