CREATE TABLE table_6655 ("Date" TEXT, "City" TEXT, "Opponent" TEXT, "Results\\u00b9" TEXT, "Type of game" TEXT)

On what date was there a friendly game against Wales?
SELECT "Date" FROM table_6655 WHERE "Type of game" = 'friendly' AND "Opponent" = 'wales'
SELECT "Date" FROM "table_6655" WHERE "Opponent" = 'wales' AND "Type of game" = 'friendly'