RCW 59.16.020: Pleadings, requirements.

The complaint in all cases under the provisions of this chapter shall be upon oath, and there shall be embodied therein or amended thereto an abstract of the plaintiff's title, and the defendant shall, in his or her answer, state whether he or she makes any claim of title to the lands described in the complaint, and if he or she makes no claim to the legal title but does claim a right to the possession of such lands, he or she shall state upon what grounds he or she claims a right to such possession.