While on 30 day block leave after deployment will a leave form and military id card be valid for international travel

If it is to your next duty station or back to a current duty station the answer is yes. Though its still best to get a VISA. But as long as you are traveling on orders(leave papers are orders) you will not have any issue.(at least I never did or heard of anyone that did my entire 3 years I was stationed in japan).