Welcome, Kyoudai.

The purpose of this guide is to tell you how to restore the licensed music from the Japanese version of Yakuza 4 that was unfortunately cut from all western versions of the game due to SEGA refusing to license the song in question - "Butterfly City" by Japanese artist "Zeebra" as well as "Don Quixote Theme" of the Japanese discount chain store "Don Quijote Co., Ltd.".
Two certain lines of dialogue in a scene during the game's first chapter have been corrected to feature a more accurate translation and are now presented uncensored.

Those of you that might be familiar with our music restoration patches for the PS3 and PS4 Yakuza titles should be right at home with this guide, as the steps to follow will be just as simple if not simpler thanks to not needing a hacked PS3 or PS4 console to use this.
This video below will give you a glimpse of what you can expect after restoring the licensed music:

Now here come the steps on how to install the patch.

First of all, you will need to download the package from the link below which contains the patch and all its necessary files:
https://www.nexusmods.com/yakuza4remastered/mods/5/

After that, extract the contents of the archive with the patch to a folder of your own choice, it's compressed in 7z format which can be unpacked using 7zip or WinRAR, though I do recommend 7zip for best compatibility to avoid any potential issues.

Next you'll need to open the folder with the game itself, naturally make sure it's installed beforehand.
You can do so by Right Clicking it in your Steam Library and then selecting Properties -> go into the Local Files tab -> and finally press the Browse Local Files button which will open the folder with the game.

Now all you will need to do is select all the files from the restoration patch you unpacked earlier and copy them to the folder with the game, overwriting the files when asked if you want to do so - this is crucial.

The only thing left for you at this point is to simply start the game and enjoy it in all its restored glory.
You can expect similar guides for future Yakuza games once they make their way to PC in the future.

They're here. Nevermind, I'm good.

I would also like to direct your attention to the upcoming Yakuza Kenzan fantranslation project being worked on by my friend, Slow, you can find more information about it as well as my patches for the PS3 and PS4 Yakuza titles over on his website which can you find under the link below:
http://yakuzapatch.tumblr.com/