The West Yakuza can be identified by their dark jackets and sunglasses. Each member carries an assault rifle and they all ride around in trucks. If an East Yakuza member is nearby, they will engage in a firefight.
The West Yakuza is led by Yamanosuke Hiroto. They were allies with the East Yakuza until Kenji Mojo said his wife was prettier than Hiroto's. Hiroto sent a disguised Cryptosporidium to lure Kenji to a trap, but was unsucessful when a traitor told the West Yakuza his plans, so the traitor was killed in his place.
The West Yakuza wouldn't meddle in Furon affairs until they claimed the Arkvoodle Cult's land for themselves, though they were repelled from the area. Both Yakuza factions were dealt a heavy loss when Crypto killed Yamanosuke and Kenji under the KGB's orders because they were stealing their thunder as the bad guys. The KGB then took control of both Yakuza factions.