Rare earths are used to make a significant part of the tiny electronic parts used in mobile phones, lcd/plasma/3d TV's, computer processors & computer electronics..
..needless to say you can understand why China reducing supply is such a big issue - especially for a country like Japan. If you want a guaranteed income (provided the company you invest in isnt a lame duck) then rare earths is the place to be, cause for obvious reasons, there is no shortage of demand.
It is an irony that the components our modern electronics rely on also happen to be the rarest in the world..
