Game On has confirmed that the first Bless Online Japanese closed beta test will be starting on April 28th and is set to run through May 4th. There is no information as yet about whether or not the CBT will be region-locked.
This may be a disappointment for Western fans as the Japanese version was announced after Aeria revealed its plans to published Bless in North America and the EU. However, Bless Source is reporting that the Aeria team is on its way to meet with the development team at Neowiz in South Korea. Hopefully we'll learn more then.
You can check out the Japanese Bless Online site for more.
Thanks to WNxbadboy3 for the tip!