Strong winds caused the cancellation of Friday's official training and were also responsible for Saturday's opening event being postponed for 24 hours but not that it affected Takanashi.
The 16-year-old, who leads the overall World Cup standings, claimed her fifth and sixth wins of the season jumping 95.5m and 93.5m for a winning total of 228.0 in the first competition in Zao.
She bettered that in the second event jumping 102m and 94m for 240.4 points beating Jacqueline Seifriedsberger and Carina Vogt first then the Austrian again and Sarah Hendrickson.
Takanashi extended her overall World Cup lead by winning both competitions in Zao with the teenager on 937 points with defending champion Hendrickson way back on 707 with four rounds left.
And Takanashi said: "I am unbelievably happy about those two victories, especially because I was able to celebrate them in front of my home crowd.
"It's great that we were so lucky with the weather and that we saw two really good competitions."