RCW 4.24.090: Validity of evidence of gambling debt.

All notes, bills, bonds, mortgages, or other securities, or other conveyances, the consideration for which shall be money, or other things of value, won by playing at any unlawful game, shall be void and of no effect, as between the parties thereto and all other persons, except holders in good faith, without notice of the illegality of such contract or conveyance.