The Japanese Yen fell past the 159 mark against the US Dollar from Monday to Tuesday, following nearly $100 billion in dollar selling by US and Japanese authorities to support the Yen. The market is skeptical about whether the Bank of Japan (BOJ) is willing to significantly tighten monetary policy to support the Yen, while also concerned that Japan's prolonged dollar selling could lead to the liquidation of a large portion of its US Treasury holdings.