The yen weakened early Friday on speculation that the Bank of Japan will re-enter the currency market to further sell the yen to protect exports, Bloomberg News reported.

That sets up a classic struggle between the Bank of Japan, which has already intervened this month --- selling the yen to weaken the currency versus the dollar -- and yen-bullish institutional investors, who believe market forces will be stronger, and ultimately lead to a stronger yen versus the buck.

The yen weakened early Friday, rising as much as 1 yen to 85.38 yen to the dollar, before strengthening late Friday afternoon, to 84.29.

Japan, the world's second largest economy is facing a sharp downturn. To try and stimulate its economy, Japan is using the financial tools used by the US and UK. The Bank of Japan( BoJ) said that it is increasing its purchases of JGB's (Japanese Government Bonds) from y 1,400 billion to y 1,800 billion per month. A central bank buying its bonds has the effect of creating new money that will flow into the economy. Japan is careful to say that this is not "quantitive easing" or just printing money, but in reality it will have the same effect.

With passage of the rescue bill, and the U.S. Treasury's upcoming actions to stabilize credit markets through a variety of tools/mechanisms, one area that is likely to experience negative consequences is the dollar.

Simply, more dollars borrowed (or more dollars printed) almost always means each dollar is worth less. Economist Richard Felson said a gradual, orderly decline in the dollar "would be expected, and is almost considered the default response, given increased U.S. government borrowing." The dollar closed Friday down about one-half cent to $1.3775 and $1.7713 versus the euro and the British pound, respectively.

Central banks monitoring dollar's level

However, leaders of the world's major industrialized economies will not, in Felson's interpretation, accept a sudden and/or inordinate decline in the dollar. "Along with increased stress on the financial system, 'brutal' currency movements, as [European Central Bank President Jean-Claude] Trichet has said, throws everything out of whack by making it hard for companies to project costs of foreign operations," Felson said. "For these reason and others I believe the major central banks will intervene to support the dollar, should the U.S. Treasury's extra borrowing or the U.S. Federal Reserve's extra lending for the bailout lead to too large or too quick of a decline in the dollar."

The much-maligned, beleaguered dollar -- driven lower for nearly a decade by series of unconscionable mistakes by United States' policy makers, may be poised to make a comeback.

But don't try to put those words into the mouth of currency trader Andrew Resnick. No sir. Dollar what? Resnick remains the skeptic of skeptics. There have been too many false break-outs and weak rallies that proved to be mere corrections in the euro's decade-long rise, in Resnick's view, to conclude at this juncture that the worst for the dollar -- and, by extension, for the United States -- is over.

A strong week for the greenback

That said, the week's data points are compelling. The dollar registered its biggest gain in two months against the euro, strengthening to $1.5006 -- or an improvement of almost 3.7% -- an enormous move in the currency market for one week. The dollar also strengthened about 2.1% versus the British pound to $1.9208, and about 2% versus Japan's yen to 110.08 yen.

What has caused the sudden turn of events in the currency market? (We don't want to use more-positive adjectives just yet.) Not the health of the U.S. economy, according to Resnick.