Dr.StrangeLove’s 1999 album Twin Suns was a tight, focused album that set up momentum for a follow-up.

A follow-up that wouldn’t arrive for another five years.

Takamune Negishi and Susumu Osada have such a successful side business as producers and session players, the duo’s output is far from prolific.

And rather than pick up where they left off with Twin Suns, the pair pretty much start from another direction, one based on introspection and the blues.

Right from the start, The River of Blue Blood establishes it isn’t going to be a rocking affair.

The sparse, cavernous percussion and lone guitar picks of the opening track, “The Garden”, evoke images of ghost towns. With a few more pedal effects, Dr.StrangeLove could have sounded like Daniel Lanois.

“Midnight Blues” is exactly that — steeped in the blues, thanks to that rough harmonica.

“Kaze -Lun-” almost sounds like an instrumental version of U2’s “So Cruel”, while “The Blue Angel” brings the band back to the indie songwriting of its earlier work.

In fact, the word “blue” figures into the title of five of the album’s 13 tracks — “Midnight Blues”, “The Blue Angel”, “The Sky is Too Blue Without You”, the title track and “Aoi Kawa” (“blue river”).

An indication of the group’s state of mind? Perhaps, if the music is any indication.

“The Sky is Too Blue Without You” is a plaintive piano ballad in the classic broken-hearted vein. A Bo Diddley-rhythm drives “Aoi Kawa -Fly Me to the Sky-” to its cautious peak, and the album’s title track is an exercise in instrumental ambience.

Even the songs in which “blue” doesn’t figure into the title point inward. A minimal guitar riff and a lot of reverb places “Falling Angel” somewhere between Interpol and Mazzy Star, while “The Apple Tree Song” feels vintage.

When Dr.StrangeLove depart from the general mood of The River of Blue Blood, it’s drastic. “Burning Spear” gets noisy with a live drum ‘n’ bass beat and guitar noise more characteristic of mono, while “Escape 2004” is a misplaced jazz excursion.

The River of Blue Blood isn’t as coherent as Twin Suns, and the writing isn’t as hook-conscious.

But the album does excel in sustaining a “blue” mood, as it were, and the strong parts of the album — particularly where Takamune and Osada fall back on their songwriting than on their production — anchor the more ethereal areas.

Just as notable is the packaging — housed in a cardboard pack, the compact disc itself slides into a bay instead of resting on small spindle.

For cardboard packages, it’s a terrific innovation. Unlike regular jewel boxes, a custom-designed cardboard package can’t be replaced if the spindle breaks.

It may have taken Dr.StrangeLove five years to release a follow-up to Twin Suns, and while the band sounds terrific when its rocking out, The River of Blue Blood makes a good case in favor of a more laid back sound.