Is it possible to prevent a japanese cheesecake from deflating or sinking?
Try letting it cool in the oven. 

The tip is from the blog "The Little Teochew", which writes:


  
  Leave to cool in oven with door ajar, about 30mins to 1 hour. Sudden changes in temperature may cause the cake to cool too quickly and collapse.
  


Further tips can by found in the blog post: Japanese Cheesecake