This was Japan's second defeat after they lost to Sweden earlier on Thursday.
Denmark placed their stones well in the first end of the match, but Japan managed to remove them from the middle, and the Japanese took the first point.
Captain Madeleine Dupont gave the Japanese a taste of their own medicine in the second end, and with the two stones best placed in the house, the Danes took a narrow lead.
Both nations struggled with the game at the beginning of the match, and the Japanese captain in particular made a string of errors.
This benefited the Danes, who continued to increase their lead.
In the fifth end, Japan reduced the deficit by claiming two points as they finally eliminated the mistakes from the initial part of the match.
In the eighth end, it was the Danes' turn to make a mistake, allowing Japan to block the Danes and equalize.
Denmark had the opportunity to take a two-point lead, but had to settle for going into the tenth and final end with a one-point lead.
The Japanese had the last stone of the tenth end, which dragged the tension out to the end.
Japan got a single point, forcing the match into an extra decisive end, where Denmark took over the advantage of the last stone.
An advantage that the Danes exploited in a distinguished manner by obtaining the winning points.