It seems TVXQ / DBSK / Tohoshinki's very own Xiah Junsu is set to release his own solo single for Japan in May. Currently, there's not much details (there isn't even a name for the single) but here's what we know thus far from Big East's fan mail. Translation courtesy of linhkawaii @ OneTVXQ:

Asia's No.1 Vocalist "JUNSU"'s Solo Single is Open for Pre-orders Now Hello everyone in Bigeast. It has been decided that "JUNSU"'s solo single "Untitled" will be released on 5/26! On this occasion, will be open to pre-order starting from 4pm on 3/23 (Tue). [Bigeast Version] ?Title: "Untitled" ?Release Date: 5/26/2010 ?Type: CD single (Picture Labeled Method) ?Price: 735 yen (tax included) ?Tracklist: 1. Untitled 2. Untitled 2 3. Untitled (Instrumental) 4. Untitled 2 (Instrumental) ?Bigeast Version Original CD? ?Picture Labeled ?Picture Labeled means that the CD will be imprinted with a picture on its surface. ?Bigeast Member's Privileges? ?Bigeast-only "JUNSU's small handwritten bulletin (jacket-sized/8P)" ?Only available for Bigeast members. ?"JUNSU's small handwritten bulletin (jacket-size/8P)" is a bulletin that includes JUNSU's handwritten comments, jacket-sized/8P. ?Enclosed Priviledges? ?Jacket-sized card ?1 random card out 3 different ones. ?This jacket-sized card is available for all versions that will be on sale. [Order Deadline] From 4pm, 3/23/2010 (Tue) ? noon, 6/2/2010 (Wed) [Delivery Method] Orders from 4pm, 3/23/2010 (Tue) ? noon, 4/30/2010 (Fri) will be delivered on release date. Orders from 1pm, 4/30/2010 (Fri) ? 11:59pm, 5/25/2010 (Tue) will be delivered on the next day of order. ?Bigeast (Tohoshinki) Official Shop ?PC http://shop.mu-mo.net/st/fc/BTC.html ?MB http://m-shop.mu-mo.net/st/fc/BTC.html -Information about Bigeast mobile shop omitted- >>>3/23/2010 from Bigeast Office