Ukagaka (), Nanika (), Sakura (), Nin'i-tan () or Nise-Haruna () is a catch-all term for Japanese software which shares a single format and function: to provide a pair of mascot characters for the user's computer desktop. These mascot characters can perform some useful functions such as checking e-mail or adjusting the clock of the computer, but are most popular as an aesthetic add-on, which "say" weird things. Characters are typically cute anime girls of original design, accompanied by a small monster or pet of some sort. However, a variety of other subjects exist on the sidelines, from video game characters to 2channel memes to humorous depictions of Hitler. Surface, shell, ghost Most importantly, the characters "talk" (typically in Japanese). What they "say" is shown in a speech bubble. Also, they have variable facial expressions (called "surfaces"). For example, they might say "It's 3. Are you still awake?" at 3:00. Or, when the user is rebooting, they might say "Oh, are you rebooting? Okay, Seeya." But usually, the two chat to each other, and the user can read their conversations (in the balloons). The contents of their conversations are usually hilarious, ironic, silly, or possibly erotic. Those lines (called "fake-AI talk") are program generated, and the personality of the character (called "ghost", in its narrow sense) depends on this conversation-generating program (called "shiori"). The character's appearance is called shell, which is implemented as several surfaces. A set of the "main" girl and her companion is vaguely called a ghost ("ghost" in its broad sense). As of August 8, 2006, 1617 kinds of ghosts are listed on the Ghost Center. Usually, a different ghost has a different shell. In order for the ghost not to repeat the same conversations (which would be boring), the user can update the data via the Internet. Additionally, if the user permits, they can talk according to a remote script (which is written in the language called "Sakura Script"). In that case, it is also possible that two or more users chat to each other using the Ukagaka system. The protocol it uses to communicate with other (local or remote) programs is called SSTP (Sakura Script Transfer Protocol). Ports 7743 and 9801 are officially assigned by IANA for SSTP. The port 7743 is not actually used for this protocol. The original Ukagaka listens to port 9801 while SSP (see below) uses the port 9821 by default.