Korean "Military Training Command" mun, looking for further details [решено]

Reverse is well preserved with the mark of the military mint. (訓) It should have the denomination under that, but the coin has a character similar to the korean "6"

Obverse is well worn but korean character "平" can be clearly seen

I looked through all my 17th-20th century krause catalogs, checked online and even ebay, but didn't see this exact variety. Can't even identify what century it is.
I would like to know what year this is, and denomination of course. I read that there are at least 5000 varieties of these holed korean coins, and only about 3000 are known. wow.

diameter: 23 or 24 mm
weight: 3.9-4gr

Thanks in advance for your input!

KM 451? Tae at bottom, series number at left.
Krause says 1857--I didn't check Hartill.

Цитата: "bjherbison"​KM 451? Tae at bottom, series number at left.
​Krause says 1857--I didn't check Hartill.

​KM 451 indeed! https://en.numista.com/catalogue/pieces76115.html

series 2

Thank you so much!