Host a DayZ Server in Japan
DayZ Manager last counted 1 ranked DayZ servers in Japan, with about 2 players on them. Japanese servers should stay in Tokyo. A Singapore detour is already a different firefight.
On the latest index, the busiest map tokens for Japan were Chernarus (1).
Slot math is local. A 60-slot Chernarus box that is full on Friday does not need 120 slots on Tuesday, and an empty high slot count is how spoof complaints start. Size the machine for the peak you have already seen on the Japan roster, then add headroom for mods. City and mod-map missions cost more than a quiet vanilla coast.
The DayZ dedicated server is Steam app 223350 on the public branch and 1042420 on experimental. Players still use the DayZ client, app 221100. Ports are UDP, commonly 2302 through 2305, plus the Steam query port. BattlEye RCon is its own UDP port, usually the game port plus 3, set in BEServer_x64.cfg or beserver_x64.cfg. RestrictRCon must be 0 if you want kicks and bans to work.
CFTools Architect is the host for that process: install, mods, updates, restarts. CFTools Cloud is the game server management product on top, including BattlEye RCon, so you are not leaving a password in a desktop shortcut. Pricing for both lives on cftools.com. This page does not invent a monthly number.
If you only wanted to play, use the Japan server list instead of renting anything. If you are opening a community, write the map, the perspective, the wipe, and the language into the hostname before you buy the second month.