Please provide some sources for your claim. I don't follow your logic on how 宝 means treasure in Japanese because "The King's balls are his treasure", and not because the character and its meaning was adopted from Chinese.

Sorry, I didn't mean to suggest that "ball under roof" means "the king's balls are his treasure". Rather it's just an easy way to remember the characters. I have no idea of the history of those characters but it is funny that 王 means king and 玉 means ball and just happens to look like king with a mark on the lower half suggesting the kings balls and that "ball under roof" 宝 means treasure.