I would suspect that the ISP is doing something weird that isn't making a ping traverse the entire internet. If you do a tracert as
@Frick suggests, you should see something similar to this because, Tokyo is a lot of hops away for both all 3 of us.
Code:
>tracert www.jnto.go.jp
Tracing route to jnto-web01.stream.ne.jp [202.79.244.228]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms gateway.concord.doane.io [10.10.10.254]
2 * * * Request timed out.
3 9 ms 10 ms 20 ms te-8-2-ur02.concord.nh.boston.comcast.net [68.85.161.173]
4 13 ms 10 ms 17 ms po-20-ur01.concord.nh.boston.comcast.net [68.87.145.73]
5 9 ms 19 ms 9 ms po-21-ur01.deering.nh.boston.comcast.net [68.87.145.69]
6 16 ms 15 ms 15 ms be-80-ar01.needham.ma.boston.comcast.net [68.85.37.41]
7 20 ms 21 ms 21 ms be-7015-cr02.newyork.ny.ibone.comcast.net [68.86.90.217]
8 40 ms 51 ms 44 ms be-10305-cr02.350ecermak.il.ibone.comcast.net [68.86.85.202]
9 63 ms 63 ms 63 ms be-10617-cr02.denver.co.ibone.comcast.net [68.86.85.170]
10 64 ms 63 ms 63 ms be-11719-cr01.1601milehigh.co.ibone.comcast.net [68.86.86.78]
11 99 ms 90 ms 88 ms be-10919-cr01.sunnyvale.ca.ibone.comcast.net [68.86.85.153]
12 87 ms 90 ms 88 ms he-0-11-0-1-pe02.529bryant.ca.ibone.comcast.net [68.86.86.146]
13 89 ms 91 ms 97 ms 124.215.192.125
14 89 ms 87 ms 89 ms pajbb001.int-gw.kddi.ne.jp [111.87.3.49]
15 196 ms 197 ms 197 ms otejbb205.int-gw.kddi.ne.jp [203.181.100.5]
16 204 ms 204 ms 204 ms cm-ote258.int-gw.kddi.ne.jp [118.155.197.181]
17 188 ms 189 ms 190 ms 118.155.202.2
18 192 ms 189 ms 189 ms Jst-NTTDATA-MBCORE01toGW01.stream.co.jp [202.79.242.166]
19 207 ms 207 ms 205 ms 202.79.242.252
20 * * * Request timed out.
The destination is dropping ICMP traffic so, it stops at the last router before the server but, you can see how distance plays a huge part in it. For me, look at the difference between 4 and 5 (crossing state boundaries,) same with 6 to 7, 7 to 8, 10 to 11. What's funny is that the 12 to 13 is country to country, probably an optical submarine cable has a relatively small jump but, at that point the latencies from the other 12 routers before it kind of add a lot to begin with.
So to me, if you do this and they all come back 10ms or so, it's probably your ISP screwing with the ICMP traffic and simply sending it back as if there was a successful response. I probably could configure my gateway to do something like that if I was so inclined, which I'm not.