Let's take a look at the Reverse Triangle (also known as Sankaku). This technique is very common in Judo newaza (groundwork) but often overlooked in BJJ circles. Triangles in general are great attacking choices as they are very hard for the opponent to escape.

The reverse triangle can be used for choking/strangling, but it also offers a unique arm/shoulder lock which is particularly effective!

Next time you're in the shin-in armbar and your opponent defends, give this a try and let us know how you get on!