Normally from columns: ends Trade and Split Counter Rotate,
while the centers Counter rotate and "anchor the (new) trailing
center for a Trade". That is, the new lead center does a Cross Run
while hanging on to the trailing center. The effect of this is that the
trailing center will do a U-Turn Back.
\sxvlines{b3s,g3s,b4s,g4s}
\sxvlines{g2s,b2e,g3w,b1s}
\sxvlines{b3e,g2w,g3e,b2w}
before Counteract
halfway
finished
While this call has a simple feel to it in the normal situation, it is commonly
used at C4 in ways that require knowledge of its precise definition.