I am not the expert.
Anchoring is a method of taking a mental/physical state and attaching it to something. Often it is anchored to a body position or awareness. It can be anchored to other sensory inputs, like the look-smell-feel of say a bottle cap.
Then by accessing the anchor you are supposed to enter quickly into that state. In the PWMS the 3-2-1 relaxation ritual is being anchored to the phrase, body state and to the mental state. So that with practice you can enter the state just as quickly as you can say 3-2-1... and faster if you become familiar with being in that state.
I believe that is one of the purposes of different hand positions when mediating on different subjects.
Remember I am not the expert.
Oooh, the pocket thingy. Anchoring is a tool, so anchoring on bottle cap, candles sticks may make it a bit combersome and inconvenient to keep the anchors with you all the time or to do without them when you don't have them. Better to anchor to something more internal.
I suspect that mind maps are as much an anchor as a probing tool.
But what do I know. 
Yoda and Miyagi. Yes Star Wars was first. However, I believe both characters are drawing apon the same cultural archetypes.
