The three castles you mention are all ranging rook (furibisha) castles. These days, due to the popularity of the anaguma by satatic rook (ibisha) players, furibisha players tend to use the Fujii system. This leads to a type of mino with the king behind the silver, previously this was only used against quick attack strategies. Apart from the Fujii system the other popular opening among professionals is the yokufutori, in this case the king is left relatively unprotected.