The article explores how high inflation rates can affect inflation stability in Japan and the US. The researchers analyzed data from 1922 to 2013 and found that when inflation is above a certain level, inflation and its volatility are positively related. However, when inflation is below this threshold, they are negatively related. In the US, this break occurs at around 2.5% annual inflation, while in Japan, it happens between 0% and 2% inflation. This means that high inflation rates above 2.5% in the US or 2% in Japan are likely to lead to more unstable inflation.