Washington Revised Code Title 11. Probate and Trust Law § 11.12.030. Signature of testator at his or her direction--Signature by mark

Every person who shall sign the testator's or testatrix's name to any will by his or her direction shall subscribe his or her own name to such will and state that he or she subscribed the testator's name at his or her request: PROVIDED, That such signing and statement shall not be required if the testator shall evidence the approval of the signature so made at his or her request by making his or her mark on the will.