Mizuumi Wiki is for the FGC, by GBL. We don't run ads or sell user data. If you enjoy the site, consider supporting our work.

Immaterial and Missing Power/Netplay

From Mizuumi Wiki
Jump to navigation Jump to search


  • What is netplay?
The Touhou Suimusou netplay is written by a person/group named Caster, and allows you to play the game over the internet. Due to the high degree of responsiveness required for fighting games, most fighters do not have an adequate utility for being played over the net; however, IaMP's netplay is quite possibly one of the best, if not the best, written for any fighting game ever.
  • Where do I get it?
RollCaster is the recommended client as it has GGPO-like netplay rollbacks, is completely in English, and has many useful features.
The original version, th075Caster, can be found here. It is not supported on this page.
Rollcaster is configured by editing the config_rollcaster.ini file.
Much of the current IaMP player fanbase can be found on #iamp located on irc.mizuumi.net. Use an irc client to connect, such as irssi or mIRC. Alternatively, you may use a web client here.
  • Step-by-step guide to making Caster work.
  • 1. Update IaMP to version 1.11. This only works with the full version, not the demo. (patch here or here)
  • 2. Download the full unlock file if you have not already unlocked all 11 characters.
  • 3. Download the most recent RollCaster and copy the contents of its exe folder directly to the IaMP directory. (th075.exe and config_rollcaster.ini should be in the same folder.)
  • 4. Make sure IaMP is not running. Additionally, stop anything that is running GameGuard or similar anti-hacking tools, as Caster is basically hacking netplay into IaMP.
  • 5. Run the Caster executable and select option 9: vs th075Booster. If all is well, you will be brought to the character selection screen and Caster is fully functional.
  • It didn't work.
  • I got a charInit() error when it started up.
There is a problem with your pad configuration and Caster is not recognizing it. This is sometimes caused by USB connections, make sure that the pad you are using is not configured incorrectly. If all else fails, use joy2key.
  • I run 95/98/ME and Caster doesn't work.
And it never will! Caster does not support archaic operating systems.
  • I run Vista and Caster doesn't work.
Update to a recent RollCaster version.
If you are using th075Caster, then edit the VISTA section of config_caster.ini and set the onoff option to 1. For Vista SP1, set StackOffset to 0x38 as well.
  • I run Linux and Caster doesn't work.
RollCaster works fine on Wine. However, the in-game keybinds don't work.
  • Something else broke.
If you followed the above guide, and Caster is still not working, you probably did something wrong.
See the below Troubleshooting section for anything else.
  • What are all these options on Caster's menu?
  • 0: Exit. Pretty self-explanatory.
  • 1: Host. Sets you up to host games.
  • 2: Connect. Attempts to connect to another host.
  • 3: Spectate. Waits for the host's game to start before connecting.
  • 4: Local 2P game. Sets up a local two player match that people can connect to and spectate.
  • 5: Get Information. This will show you the status of a host, whether they are in a game or not and who's being used.
  • 6: Connect (Persistent mode). This option will connect, never give it up and never let it down.
  • 7: Relay. This option allows two parties to connect to each other via a neutral third party, thus bypassing problems with routers and port forwarding.
  • 8: Test hosting port. This option will to see if your port is forwarded properly.
  • 9: vs th075Booster. This option tests to see if your netplay is working properly. If everything is okay, you should be brought directly to the character select screen; if not, you will see the introductory movie. Also, select this option to initiate the th075Booster program and to play against the modified AI.
  • 10:Practice dummy. This is a practice dummy that is included with Caster that has some features not available normally in IaMP.
  • 11:Script. This is an experimental feature that lets you write scripts for the AI. Undocumented.


  • How do I host a game?
Make sure you have the selected port (usually port 7500/UDP) open and accessible. This requires port forwarding if a router is involved, and also depends on if your ISP allows incoming connections or not. If you are not sure what any of this means, have the other side host instead if possible. Visit www.portforward.com for details.
Once you've got that done, use option 1 in Caster and tell your opponent your IP address. You can use www.whatismyip.org to get it quickly.
  • How can I tell if I can host?
Use option 8 in Caster and tell it to connect to on port 7500. It will either report "Port: OK", which means you can host, or "Port: BAD", which means your ports are not forwarded and you currently cannot host.
  • Neither of us can host/have access to the router. How can we play?
There are a few options.
The easiest option is to use the Caster relay hosted on Mizuumi itself. In order to use this, have both parties use option 7 to connect to fgc.shib.live on port 7500. If everything is set up properly, then Caster will initiate the game. This is a direct connection to the other player and will not add any lag. No further software is required. This is the simplest and recommended way to connect if neither party can host.
The second, harder option is to use Hamachi, a program that emulates LANs over the Internet. This will allow you to connect to people using virtual network IPs without any need for port forwarding. The current "official" #IaMP Hamachi networks are: iamp, password is eyeamp; eyeamp, password is iamp; and th7.5, password is iamp. To host, simply use the Hamachi-assigned IP instead of your normal one and make sure the person you are connecting to is on the same network. Note that Hamachi has a limitation of 16 people for the free version, and that the servers that they use may go down on occasion. This option is obsolete and is only recommended for use when nothing else works.
  • How do I connect to other people? Do I need to have any ports open?
No. Connecting to other people doesn't require any open ports forwarded, but your firewall should not have 7500/UDP blocked if it prevents outgoing connections.
  • Can I spectate other games?
Yes. Use option 3 to connect to a game after both parties have already started. This will automatically wait until the game has started before trying to connect and will never snipe a game.
You can spectate any Caster client that is running a game, even ones that are currently spectating other players.
If Caster responds with 'Status: BAD' then that player is blocking his game from being spectated.
  • Can more than one person spectate?
Yes. This does not cause lag for the players. If there is more than one person spectating, any after the first are rerouted through the other spectators. If the first spectator disconnects, any that are watching will also disconnect along with him, and must reconnect in order to continue watching. It's a hassle.
  • Why is the match going so fast?
You're behind where the match is actually "happening". Caster will force IaMP to run at an accelerated rate to catch up until you are at the point where the players currently are. You can press the backspace key while in a match to make it play back at a normal rate.
  • What is this buffer thing?
The buffer is what you set to control how far away your opponent is, time-wise. RollCaster recommends a buffer for you to use, just press enter if you like what you see.
You can enter 0 buffer to make it refresh the latency value it reports, in case the value seems high due to temporary connection issues, such as forgetting to turn off torrents or whatever.
Here is a table of latency to recommended buffer:
MS: 0-16 16-48 48-80 80-112 112-144 144-176 176-208 208-240 240-272 272-320 320+
Delay: 1 2 3 4 5 6 7 8 9 10 N/A
These are some values that should work provided there is a stable connection. If the frame rate is choppy or low, bump the buffer up while in-game to compensate.
  • I didn't see that prompt at all. It just says 'Now waiting.'
That means that you are player 2. Only player 1 can set the buffer. It is randomly determined who gets which side normally. The playerSide option in config_caster.ini can be set to prefer either player 1 or player 2, but if both players choose the same setting it will be randomly determined anyway.
  • Can I change the buffer without restarting?
Yes. Press 1-9 or 0 (not on the numpad) after a match has started. You will see a debug message stating that the delay has been changed. This will change the input delay for that player only, and the input delay of the other player will be unaffected.
  • What's this rewind thing?
New to RollCaster is GGPO-like rollbacks that hides internet latency and reducing your input delay, by guessing at what the opponent will do and correcting when it is wrong. By default, it will rewind at most 3 frames. This is the recommended value as increased amounts will cause a severe amount of warping.
RollCaster has two settings, one for minimum input delay, one for maximum rewind amount. Input delay is how long from when you press the button until your inputs take effect. Configure these as you wish.
  • Can I change the rewind without restarting?
Yes. Hold shift and press one of the buffer setting keys, as above, to change the rewind amount. You may not set it higher than the buffer value directly.


  • IaMP failed to start when someone connected.
  • Make sure your Caster.exe file is in the exact same directory as th075.exe. Not a shortcut, but the exact same folder.
  • Make sure you're running at least Windows 2000 or higher.
  • Make sure your pads are plugged in, and if you don't use pads, make sure your config.exe is set to use keys only.
  • Make sure IaMP is not already running before you connect. Caster will start up IaMP for you.
  • Make sure that the directory containing IaMP doesn't have any Japanese characters in its name.
  • IaMP starts, but doesn't take me to the character select screen.
Choose option 9 by yourself. Caster should open IaMP and send you straight to the select screen. If not, remove all Japanese characters from your IaMP folder and try again. If it still doesn't work, reinstall and repatch IaMP.
If Caster gives a "charInit() failed" error, there is a problem with your joystick configuration where IaMP is seeing one controller and Caster is seeing something different. Try connecting it to a different port, using keyboard controls, or joytokey.
  • My enemy started doing weird things and then just stopped. What happened?
The game desynched due to dropped packets or whatever. Just close the game and reconnect through the netplay utility. Caster will notify you of when this happens by stating "ERROR : deSync", and a sound can be configured to play at this time.
  • The game just froze up!
Same thing as above.
  • It's slow and I'm getting less than 60 fps.
There are numerous causes to lag in the game. Here are the most common:
  • Turn off all downloads, torrents, whatever is using your connection. Make sure the other person does as well.
  • Try connecting to the host and see what the ping is. Note that across the continental U.S. you should have full 60 fps provided both sides are working properly; outside and you will start experiencing lower framerates.
  • If the other person's computer cannot handle effects, the delay will be manifested whenever multiple projectiles are on the screen or when counterhits happen. The only fix for this is to have them get a more powerful computer.
  • If the 1/2 framerate option is checked the game will be capped at 30-31 fps, even if both players use the option.
  • I can't select day stages!
If Remilia is involved, no day stages may be selected. She's a vampire and shit.
  • I can't select Sakuya-day/Youmu-day/Suika!
These stages have been softbanned on the netplay because the color palette used makes certain bullets difficult to see.
These may be re-enabled by You can also enable them on the fly by having player one press the backspace key during the stage select.
  • My replays don't play back correctly!
A desync fix was added to Caster that causes issues with replay playback. Use the replay watcher to view replays created by them.


NOTE: This is for IaMP matchmaking, NOT Melty Blood. For Melty Blood, visit #mbac on irc.efnet.net, #srm on irc.pyoko.org, or #meltanjp on irc.irchighway.net.

  • Where can I play English-speaking people?
#iamp on irc.mizuumi.net, or the IaMP discord here.


  • How do I configure Caster to my preferences?
Open the "config_rollcaster.ini" file. Use 0 and 1 to turn options off or on. Most of the options should be fairly self-explanatory.
  • What other random commands are there?
RollCaster's readme file has a listing of all hotkeys available in English.
Immaterial and Missing Power
General FAQNetplayControlsMenusHUDGlossaryLinks
Mods NetplayRollcasterth075toolEnglish TranslationColor EditorFramedata DisplayerReplay Renamerth075boosterBGM Changer
Characters Reimu HakureiMarisa KirisameSakuya IzayoiAlice MargatroidPatchouli KnowledgeYoumu KonpakuRemilia ScarletYuyuko SaigyoujiYukari YakumoSuika IbukiHong Meirin
General Mechanics MovementMixupBombSpell Card
Specific Mechanics EsotericsAutoguardCommand InterpreterAttack LevelsStagger SystemHitboxes
Community #iamp IRC Channel InfoTournament Results