Children of the Sea, Volume 1 - Daisuke Igarashi My first Seinen, although I am not sure why. To me, it does not qualify as Seinen, but maybe because I though Seinen was focused on older men?

The art is beautiful. The mangaka is one of those artist who puts more effort in the background, in the scenery, than in the characters. The water, the animals... everything is very detailed. One of the things I liked the most were the different drawings of a same scenery, from different angles. And the colorful parts looked like they were painted with watercolor. Very beautiful.

The story, of the other hand, was very slow. I could not get into it, and neither into the characters. It is a long first volume, and just the last chapter was starting to get interesting.