Hah, both posted at the same time.

It seems they are taking the time to explain the historical references and I bet their subtitles are easier to read.

Like most of our recent projects, Irohanihoheto will be encoded in the XviD/Vorbis format in a Matroska container. The dialogue will be hardsubbed onto the video, but the additional notes are softsubbed (and off by default). These additional notes aren’t required, but the show relies heavily on Japanese history; the notes will most likely enhance your enjoyment and comprehension of the occurrences that take place throughout the episode. You will need VSfilter to view the additional notes properly; if you’re using VLC, good luck with that. Mplayer users, you may want to consider upgrading to the 1.0 RC1 build and use the new -ass option (see the manual page for details).
Source: Oyasumi