Board Thread:News and Events/@comment-26005122-20170331160530

Every month, for the Japanese version only, a specific selection of Tsums will be made available in the Premium Boxes, as opposed to offering every Tsum currently available. This will increase your chances of getting a specific Tsum you want, instead of a really low random chance among all the Premium Tsums.

The Tsums available for the month of April are: Any Tsum Tsum not listed will not appear in the Premium Boxes during the month of April. The change was likely implemented to help people have a better chance of increasing the skill level of a particular Tsum they want. 
 * Fantasmic Mickey
 * Hercules
 * Prince Phillip
 * Mike
 * Sulley
 * Little Oyster
 * Olaf
 * Thumper
 * Ana
 * Sebastian
 * Jessie
 * Lotso
 * Angel
 * King Triton
 * Aladdin
 * Evil Queen
 * Nick Wilde
 * Nala
 * Queen of Hearts
 * Dory
 * Jafar
 * Maui
 * Stitch
 * Marie
 * Woody
 * Alice
 * White Rabbit
 * Bambi
 * Miss Bunny
 * Maleficent
 * Ariel
 * Rapunzel
 * Pascal
 * Baymax
 * Belle
 * Beast
 * Surprise Elsa
 * Birthday Anna
 * Lightning McQueen
 * Randall
 * Jasmine
 * Pinocchio
 * Princess Snow White
 * Princess Aurora
 * Maleficent Dragon
 * Judy Hopps
 * Simba
 * Nemo