Positions 3

There are three main types of positions in the ground grappling game: Pins, Holds, and Transitions.

Transitions
Transitions, or transitional positions, are positions that offer a slight advantage to the practitioner. Typically, these are more difficult to keep than Pins or Holds. Also, submission opportunities are more severely limited. 

Nomenclature
Half guard - note: the half guard is its own beast, more to come.
Side port / starboard - you had a side pin, but the opponent rolled onto his side, either facing you or away.
Turtle - opponent is curled into a ball on all fours.
Sprawl - opponent shot, you sprawled, now he is turtled up.

Submissions
With the exception of half guard, all of these Transitions offer opportunities to catch one's opponent in a submission hold. Most notably, all of these positions offer an opportunity for juji gatame. Here are some other opportunities:

Side port - ude garami
Side starboard - hadaka jime
Turtle - waki gatame, ushiro sankaku jime, hadaka jime
Sprawl - (mae) hadaka jime, yoko sankaku jime

Transition to other positions
All of these Transitional Positions offer the practitioner opportunities to move to other positions.
Side port - modified mount
Side starboard - back, modified mount
Turtle - back
Sprawl - back

Half Guard
The half guard is best looked at from its two inherent iterations: top and bottom.

Objective on the bottom is to escape.
Common positions to end up from escaping half guard bottom include guard, mount, and back.
Ude garami and juji gatame are possible from bottom of half guard, but is very situational. 

Objective from the top of half guard is to pass to a dominant position.
Common places to end up include mount and side.
Juji gatame is possible from top, but very situational.
Striking from top of half guard is common and effective.

Sportive collar chokes
Okurieri jime and kataha jime are possible from side starboard, turtle, and sprawl.
Sodeguruma jime is possible from half guard top.


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