I thought this was a brand-new spider. Turns out it's so old I've never met it before; Forums search turns up a fistful of posts, none with numbers above three or four digits. Back around 2005 everyone seemed to be flagging it as a new Chinese search engine.
:: insert irrelevant allusion here to "Brazil is the country of the future-- and always will be" ::
Here they are snuffling around my test site.
18.104.22.168 - - [24/Apr/2013:12:39:58 -0700] "GET / HTTP/1.1" 301 557 "-" "YisouSpider"
22.214.171.124 - - [24/Apr/2013:12:39:59 -0700] "GET / HTTP/1.1" 200 910 "-" "YisouSpider"
Apparently they're a tentacle of Yahoo! Slurp; the IP bears this out.
As long as I was there, I mopped up all the Chinese /15 and /16 within the 110 sector. I don't go below /14 unless something draws my attention to the range. Robotic activity definitely qualifies. No, I don't know why I don't have a global block on UAs containing the element "spider". But I'm sure there's a reason.