"Lush" and "well-rounded" are the prime adjectives to describe Aiko's Himitsu.

In the mid-2000s, Aiko was the leader of the female J-pop pack, and although her eighth album marked a relative dip in sales, it reaffirmed her sound as the ultimate blueprint for Japanese romantic pop.

The album focuses on a single type of music -- sunny, ultra-melodic ditties utilizing acoustic guitars, light jazz piano, and flourishes of string arrangements -- to create a lighthearted cinematic mood that, while close to trite, is never melodramatic.

The sheer amount of harmony found on Himitsu seems calculated to please the ancient Greeks, and every now and then the sound veers toward timeless -- Aiko's type of crooning wouldn't be out of place in a 1920s café chantant and is as likely to stay in demand decades after it was recorded.

However, being flawless is not always a good thing.

Aiko has the same kind of problem as Gackt in the rock part of Japanese scene: the sound provides too little to grab the listener's attention, and so the music recedes into the background.

She may recall Gabriella Cilmi on "Gakkou," but lacks her swagger; she uses some rock guitars, drum loops, and '60s pop brass arrangements, but those are too subdued and become lost behind the general stream of sweet melodies.

In a way, every J-pop singer goes for this type of sound, and it's just that most either don't have the skill to pull it off in such a sweeping fashion, or get distracted by other influences, such as jazz, punk-pop, or visual kei.

Aiko's sound is the purest of all and, as such, will please those who hanker for the emotions it exudes, or simply want an hour of positive -- if undemanding -- music.

However, not being afraid to write something other than the perfect rom-com theme might have actually benefited her.