Not Japanese
Just about where the center of the hole is.
3
you dont
To fit the hole.
"Square peg in a round hole" means something that doesn't fit in where it is; the opposite is something that is exactly where it should be. An example of this might be "hand in a glove".
Belgium coins with a hole in the center are the 5, 10, and 25 Centimes. The value of these coins minted in 1905 ranges from $1 to $3.
Not in modern times
Downward. That is, toward the center of the Earth.
There are many old Chinese coins that have a square hole in them. These coins could date back 2400 years ago.
The event horizon of a black hole is a spherical area round the center of the black hole; it has a radius proportional to the mass of the black hole - a radius of about 2.95 kilometers for every solar mass.
1608*22/7
The 19th hole can be the first playoff hole after a round of golf, but it is another name for the bar after the round.
A a sweet round pastry with a hole in it is a doughnut.
A port hole ?
You do not provide any detail. If it is a general circulation coin, it is worth nothing. Modified coins are worthless. There were no British coins minted with holes in the centre. On the other hand, you may have a medallion of some sort.
Just about where the center of the hole is.
Yes. Consider the toroid. (A doughnut) The center of mass is in the center of the hole in the middle.