Written by Rachel Yarwood
"Shinsekai" begins with pleasant and inviting opening vocals (Ooki Nobuo) which really do take your breath away for each verse. However, as the chorus enters this is replaced by louder and harsher sounding vocals, which is a bit of a shame, as it seems as though Ooki is trying to compete with the volume of the instruments. 
The track stays mid-tempo for each verse and for the chorus we see a rise in rhythm and in volume, as mentioned, which gives the sense of a certain urgency. Together with the vocal change, the drumming also changes and instead of a calming beat we have a rapid tempo and the near continual crashes of the drum cymbals (Urayama Ichigo) which is perhaps a little too much. The noise of the cymbals especially might be a tad overworked and depending on how loud you like to have your music, you may find yourself turning this track down a little bit. 
The volume of the chorus is arguably the only down side to "Shinsekai" as overall this track is a nice upbeat, catchy, decent rock song to open the single with. 
"Swayed (second line)" is remarkably different in style. There is a good tempo from the hand beaten percussion instruments and a simple melody of acoustic guitar. The vocals begin calming and serene once again and as the song progresses they become more strong and melodic. There is also an addition of violin which contributes to the interesting sound of this song and yet, eventhough this track is the most intriguing genre wise, it probably doesnt grab your attention in the same way as the first track does. 
"Under the Rain (Acoustic)" on the other hand is both powerful and beautiful. The fact that, although this song is acoustic, the bass line (Satou Masatoshi) and the drums remain through out and this gives the track a lot more depth than it would do if these were left out. Altogether this track is a lovely end to the single. 
"Shinsekai" will be released officially on the 19th of December ahead of their full length album (which will bear the same name) release at the end of February next year. 
This single will be released in just the one edition and it will feature the three tracks as mentioned; "Shinsekai", "Swayed (second line)" and "Under The Rain (Acoustic)".