... because the bidder name doesn't connect up 
with any of the handles Nick has ever used.  
The "jp" at the end implies a Japanese bidder or 
service.  I've only once won an AC/DS auction in 
this way, by just 500 yen, and in that case I 
assumed that I'd out-bluffed the underbidder, who 
didn't know how close s/he came to my limit. (And 
I got a good deal even at that ... ridiculous 
bids tend to make cels go for ridiculous 
prices.)  shadowcat might just have thought 
his/her bid was just as "ridiculous" as your bid 
and was too surprised to get outbid to go on even 
2 more yen.

I was browsing an auction recently (and counting 
my money to see how high I was willing to go on 
it). Up to 30 min. before the end the high bid 
was in the 18k range.  Then I refreshed, and the 
high bid was 220k!  Holy moly!!!  A quick check 
showed what had happened: bidder A had left a 
massive reserve bid to be certain of getting it, 
and bidder B tried to overwhelm bidder A with a 
massive raise in the ante.  Result: instantaneous 
10x-plus raise in the price of the cel. I've also 
seen this happen on eBay during the last seconds 
of an auction, when two snipers catch each other 
in their crossfire.

It's also possible (though not likely) that the 
seller might have shilled the auction.  This 
person would gain much more than Nick from doing 
this.  (The difference in DS commission between 
21k and 29k isn't going to pay any of Nick's 
heating bills, after all.)  But in this case I'd 
expect the shiller to nibble up to your bid, 999 
yen at a time.  

I'd just chalk it up to experience ... online 
auctions are like that.  And be careful not to 
bid money you're not willing to spend ...

...Sensei tells himself as he shakes his 
finger at his own image in the mirror...<>