*This does not affect OP's trip in June*
FYI, Himeji castle is going to be under restoration.
From April 2010 to 2014, it is covered in a temporary construction tent which you can see at:
http://himejijo.ninpou.jp/guide12.html
The website says, "Don't be dissapointed. This is a rare and good chance to have a look at the outer walls from a short distance." Look at the tent. Can you see something like ants ? They are in visitor accecible area.
Inside ? It says it is open throughout the costruction period.
Info from the city (Japanese)
http://www.city.himeji.lg.jp/s110/2212786/_11311.html