Hi @iocc and @elljay,
Seemingly the IPv4 address of the servers https://www.ntppool.org/user/takerukoushirou are incorrectly categorized to be in Switzerland (ch) instead of France (fr). Both geoip and traceroute shows that the servers are located in France. I have inter-country packet delays (> 20ms) from Switzerland. The IPv6 addresses are correctly categorized to be in France. Since these servers are not mine, you may wish to check with the owner.