depth

The depth filter is a numeric filter whose value is the depth of the current position. Any mainline position has variation depth of 0.

If X is a position other than the initial position, then:

• if X is the primary child of its parent, its variation depth equals the variation depth of its parent
• if X is a not the primary child of its parent, its variation depth is the variation depth of its parent plus 1.

Thus the two lines below match the same set of positions:

     variation
     depth>0