Sometimes called left hands, By the left is an alternative way for two dancers to Take hands when Crossing or Turning or Travelling together, side by side. When Travelling together, the joined left hands should be in front at chest height; for all other movements, the hands should be as described above in Take hands with relative movement.
Many Scottish Country Dancers forgetfully Turn by the right when Turn by the left is prescribed, with uncomfortable consequences on those many occasions when the next Figure fits only a Turn by the left.
By the left is also a qualification of a Figure, such as Cross, to indicate that the dancer should pass to the left of (i.e., Give right shoulders to) the approaching dancer (or Couple).
For example, here are some Scottish Country Dances in which the term, By the left, is used in either the Minicrib or the Maxicrib Dance instructions or both -
Alex Doig's Jig