Yeah, Mitch had it right: BC= Backwards Compatibility (because I am super lazy and abbreviated it; sorry for the confusion). It simply means it can play PS2 and PS1 games... I heard that the more recent models are limited in that aspect; I know there was a list posted for the 80 GB of compatible games and what problems you might have while playing some.
@Fu- I don't remember posting that, but I recall what you're talking about. I think that whomever did post it said it went something like this...
SW-Wei-Wu-Shu (I think). SW and Wu's connects with one another pretty well; Nobunaga instructs Sakon to to go Wu, to help them out. Big mistake happens, Cao Pi chases down Sun Ce (and lets him go), and all the while, Shu is just lagging behind... I can't recall exactly how Shu's story fits in with the others, though.
However, I do know that after Sun Ce defeats Lu Xun's army, Gan Ning and Ling Tong remained together until the next Wu stage (where Xing Cai took them in and was commander), while Lu Xun got himself isolated, where Nobunaga saves him (Gaiden stage). After Sakon and Sun Ce defeat Xing Cai, Ling Tong and Gan Ning are separated, where Ling Tong runs into the SW army, while Ning ends up with Nagamasa and Oichi. Because Gan Ning gets caught up with those two lovebirds, as well as Cao Pi chasing down the 'traitorous' Sun Ce, that at least connects those three together in some kind of timeline.
I just can't figure out Shu's involvement; they were more stand-alone, I think. The only way I can connect them with the rest of the armies is Wu's first stage, where Ma Chao, Yue Ying, and Jiang Wei were together, but upon defeat, scattered about. Ma Chao rushed on his own and protected villagers (SW's Gaiden), Jiang Wei ends up in the Nanman area where he meets up with his own kingdom (Gaiden), and Yue Ying was inevitably captured (Shu's second stage... I think). I think Shu's army coincides with Wei's and Wu's story when they were forced to put their resistances down, though I'm not sure exactly how well SW and Shu's story mode coincide.
If Koei really wanted to, they could have done a lot more with that angle, but I think they were more focused on fan service, than anything epic.
Sorry for being absent, guys... I was trying to finish the last trial on Trials and Tribulations. Just in time, as DW6 should be arriving tomorrow!