Historical Rules · 28 April 2017
Rule 702.14c
Official source text from the 28 April 2017 Rules release
A creature with landwalk can’t be blocked as long as the defending player controls at least one land with the specified subtype (as in “islandwalk”), with the specified supertype (as in “legendary landwalk”), without the specified supertype (as in “nonbasic landwalk”), or with both the specified supertype and the specified subtype (as in “snow swampwalk”). (See rule 509, “Declare Blockers Step.”)