Write SQL query to solve given problem: How many All Star players who played in the 1973 season were black?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(DISTINCT T1.playerID) FROM players AS T1 INNER JOIN player_allstar AS T2 ON T1.playerID = T2.playerID WHERE T2.season_id = 1973 AND T1.race = 'B'