The first thing that we must do is to set windows to support the japanese language. We do this by going into the control panel(start menu->settings->control panel) and then choosing Regional Options.

Here we put a check in the box next to japanese. Now, you don't have to set japanese as your default language to be able to view japanese, but you will need to set it as default in order to enter japanese text into mirc, so you may do that now if you'd like. Also, note that you may leave your locale above to be whatever you'd like. When you're done, hit "Apply" this will require a reboot.
Section ニ: Configuring mIRC
Now it's time to configure mIRC to display japanese. In mIRC go to File->Options->IRC->Messages.
Section 三: Installing the language bar
The first thing we need to do in order to be able to type japanese text into mIRC is to set japanese as the default language. Don't worry, this will affect very little of anything else. To do so, go back to Regional Settings where we were in section 一. Hit the Set Default button, then choose Japanese and hit OK. This will require a reboot. Now that you've done that and reboot (unless you did it earlier when I mentioned that we'd need to later) we're ready to install the language bar. Go back into Regional Settings again and this time click on the last tab which is labeled "Input Locales".
Section 四: Keyboard Hotkeys and Shortcuts
The keyboard hotkeys and shortcuts for the language bar can be changed, but I'm going to explain the default values to you. (You wouldn't change anything unless you already knew what you were doing, right?) To switch between english (or whatever language) and japanese mode hit Alt-Shift. When you're in english mode, the language bar icon will be a blue box with the letters "EN" in it. When you're in japanese mode it'll actually turn into 2 icons one which looks like a pen and another which looks like a ball & paintbrush. Also, when you're in japanese mode a bar with a few icons on it will pop up just above the taskbar.
Section 五: Using the language bar
We're almost there. Using your language bar in japanese mode may seem akward at first. Here's how we do it. Choose the mode you wish to input in (hirigana for instance). Now type whatever you want to type into mIRC as romanji. For every 2 (or so, depending) characters you type, they'll be transformed into the character mode you selected. You'll notice that whatever you type is underlined. When you're done with a word, if you're happy with that word then press enter and the underline will disappear. Now you may press the spacebar and continue typing. If you want the word which you just typed to show up in another character mode (katakana or kanji for instance) then hit the spacebar.
Section 六: Omake
Since setting up my computer this way it's been mostly unintrusive, however there were a few caveats that I thought would be worth mentioning.
Thanks to everyone who helped me with this information and japanese in general including:

Check the boxes SJIS/JIS conversion and Multibye characters. That's it for this menu, the other options are irrelevant for this guide's purposes, so click OK. That sets mIRC to be ready to display japanese, but we're still not done yet, we must select a japanese font. Now join the channel which you wish to speak japanese in if you haven't done so already. Then in mIRC choose
Tools->Font.

Now you must choose a font which will allow you to view japanese. Choose the font under the "Font" label and under the "Script" label choose "Japanese". Not all fonts have a japanese script, so keep scrolling through the fonts until you find one that you like that does. If you want to use this font in all irc channels then click "Set as default channel font" otherwise you'll have to repeat this process for every channel in which you want japanese support. One more thing that's worth noting, use the Sample Text box to preview the fonts. Many of the fonts are made for vertical text and look silly in mIRC. When you're happy with a font, click OK.

Hit the Add button and select Japanese for both Input Local and Keyboard layout/IME. Click OK and then you'll probably need yet another reboot. When you're computer boots back up you should have a new icon in the taskbar at the bottom-right of your screen. This is the language bar.

This is the language bar. In the language bar, click on the left-most icon. You should get a list of input modes like Hiragana and Katakana. Choose whatever one you wish to input as. "Direct Input" is romanji input. You already learned that you can switch through english and japanese mode by hitting alt-shift, to switch between kana/kanji input and direct input (which is basically the same thing we were doing before but in a different way) hit alt-`. That's alt and the key to the left of the 1.

Keep hitting the spacebar until the word shows up as you desire. You'll see a list of ways to display the word and each time you hit space it'll scroll through that list. When you're satisfied with how it looks press enter and then continue typing. This may seem akward at first, but this way we can quickly type mixtures of hiragana, katakana, and kanji without constant changing the mode we're typing in. That's it! さよなら!
Written by BludClot. I can be reached at BludClot at hellokitty dot com.

At the bottom there is a section called Default Code Page. Select 437 (OEM - United States) in the dropdown list and hit OK. From now on your should have your usual, American DOS back.
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