Complex sentence: Rōnin, masterless samurai, were not allowed in and neither were the prostitutes let out, except once a year to see the "sakura" cherry blossoms and to visit dying relatives.
Split into simpler sentences: Rōnin, masterless samurai, were not allowed to enter. The prostitutes were never let out, except once a year to see the "sakura" cherry blossoms and to visit dying relatives.