Spitz belong to the top league of J-rock, right there with B'z and Glay, and for the Japanese scene it means that the band gets by on sheer songwriting, not stylistic peculiarities.
The style of their Sazanami CD is, indeed, blurred to the point of becoming "just rock", but when the first emotional climax sets in 40 seconds in the opening song, there's a great chance no one would care, especially seeing that the band has much more in store.
Spitz even allow themselves to be predominantly a guitar band, not only building their songs around acoustic riffs, but letting the guitar handle most of the arrangements as well, while adding some synthesizer tinkling over the echo and the reverb.
The U2 influence is obvious, but the outcome is actually strangely similar to the Cure's airier moments -- think "Friday I'm in Love," which gets quoted, or even ripped-off, on "Gunjou." The main point of the Cure is often considered to be the interposition of the cheerful music with the morose and weepy vocals of Robert Smith, and Sazanami provides a unique opportunity to hear how it would work without Smith sowing the seeds of depression far and wide.
The answer is still satisfactory, although, expectantly, very poppy -- but Spitz make up for this levity with an array of arena rock choruses and semi-ballads that help to keep the listener thrilled from the first to the last song of the record.