Japan became the first major economy to eliminate interest rates.
Many nations used that tactic to support their economies.
The Bank of Japan is expected to keep its main rate below zero on Friday. That is not good for its currency.
The Japanese currency has long been seen as a safe place to put your money.
That status is shaky at the moment. It has lost more than 20% of its value against the US dollar this year.
Interest rates in Japan and the US are different.
The US Federal Reserve has raised its main interest rate three times since March in order to fight the rising cost of living.
A higher interest rate makes a currency more attractive to investors.
There is less demand for currency from countries with low rates.
The country's finances are believed to be reflected by the weak yen.
In the last 30 years, the economy has not grown. The nation is the most indebted in the world.
The population of Japan has the highest proportion of older people in the world.
There is no reason for the Japanese currency to strengthen.
The Japanese currency is expected to hit 180 against the US dollar before collapsing in value.
The economy is not strong enough to handle higher interest rates.
Japanese consumers are struggling with rising inflation but that has been welcomed by policy makers who want prices to rise.
The bank's current policy is needed to reach its 2% inflation target, according to Mr. Kuroda.
Deficiency, or falling prices, is bad for an economy because consumers tend to hold back on buying big ticket items because they think they will be cheaper in the future.
For almost two and a half decades, Japan did not intervene in the global currency market to support the Japanese currency.
Authorities spent $21 billion as the currency fell last month.
It helped for a short time, but then the currency went from 150 to the dollar in a single day.
The new intervention is estimated to be $37 billion.
Even though traders said they saw signs of another intervention earlier this week, the Japanese government has yet to confirm it.
Attempts to prop up the Japanese currency will only have a short term effect, according to experts.
The former senior official at Japan's finance ministry said it was to show the position of the Japanese government.
Everything Japan buys is more expensive because of the weakness of the dollar.
The country imports a lot of oil and gas The amount of money it spent on imports increased by 42% because of exchange rates.
It's good news for businesses. The money that Japanese exporters make abroad is more valuable at home. About 15% of the country's economic activity is exported.
Japan's consumers have seen their purchasing power decrease. Ten years ago, 10,000 Japanese dollars would buy an item worth $132, but now it only gets you something worth $68.
Average salaries in Japan haven't risen in over 30 years.
When people need to use the yen to pay for things overseas, it's a bigger problem.
People didn't feel much of an effect when Japan's borders were still closed because of the falling value of the Japanese currency.
The sliding value of the Japanese currency makes it more attractive to tourists as their holiday money goes further.
More than 30 million foreign visitors came to Japan in the year.
Within a year of the country fully reopening, Goldman Sachs predicts inbound spending could reach 6.6tn yen, which is more than the number of tourists.