Other side of the world

So I was wondering what is exactly opposite to Tokyo in the world…
First I found out that this is called the antipodal point.
Turns out that the calculation is pretty simple.
– The new latitude will simply be the reverse North/South
– The new longitude will be 180 – the old longitude and then reverse East/West
For example, the antipodal point for Honolulu at 21.3N, 157.8W is 21.3S, 22.2E – somewhere in Northwest Botswana.
Tokyo just falls off of the coast of the southern-most tip of Brazil.
Here is a site showing this: