How many publishers in Japan released a game on X360 in 2011?
in Japan refers to region_name = 'Japan'; on X360 refers to platform_name = 'X360'; in 2011 refers to release_year = 2011
SELECT COUNT(T3.game_publisher_id) FROM region AS T1 INNER JOIN region_sales AS T2 ON T1.id = T2.region_id INNER JOIN game_platform AS T3 ON T2.game_platform_id = T3.id INNER JOIN platform AS T4 ON T3.platform_id = T4.id WHERE T4.platform_name = 'X360' AND T3.release_year = 2011 AND T1.region_name = 'Japan'