From Parallel Waves, Eight Chain Thru, or other applicable formations.
  - Arm Turn 1/2;
- Centers Cast Off 1/4;
- Very Centers Trade;
- Centers Cast Off 1/4.
Ends in Parallel Waves.  
  This is a 4-part call.
Notes:
- 
Swing Chain Thru is the same as Spin Chain Thru [Plus] except
    that each 3/4 Turn is replaced with a 1/4 Turn.
- 
Think 'half, quarter, half, quarter' or 2-1-2-1.
- 
Swing Chain Thru can also be called from an Alamo Ring: start
    with the R-H (unless otherwise specified) alternating hands Cast
    Off 1/2, 1/4, 1/2, and 1/4. Ends in an Alamo Ring.
    This usage is rare, and somewhat controversial.  It would be wise for the caller
    to specify the starting hand.
- 
For checker-pushing callers: From Parallel Waves, Swing Chain Thru
    is equivalent to 
Rims Trade Back [C2].
Swing Chain CONCEPT [C4]:
 Replace all 3/4 Turns (including  Star 3/4) of the given call with 1/4 turns.  
  For calls whose  name begins with the words 'Spin Chain' the word
  'Spin' is replaced with the word 'Swing.'  For all other calls the word
  'Swing' is inserted before the name of the call.  Examples: Swing Chain The
  Line, Swing Chain The Gears, Swing Alter & Circulate.
Spin Chain Thru [Mainstream] (Rod Blaylock 1967):
 From Parallel Waves, Eight Chain Thru, or other applicable formations.
  Arm Turn 1/2; Centers Cast Off 3/4; the Very Centers Trade; Centers Cast Off 3/4.
  Ends in Parallel Waves.
  This is a 4-part call.