Top-selling phones in Japan during first week in February

Yaromir at Japan's Cellphone Edge points to some interesting data from GfK about the Japan handset market. Below is a list of the top 3 selling handsets in Japan during the first week of February (01/30/06~02/05/06) for Japan’s top four carriers, NTT DoCoMo, KDDI au, KDDI Tu-ka and Vodafone:

NTT DoCoMo:

1. NEC N901iS
2. Sharp SH902i
3. Mitsubishi D902i

KDDI au:

1. Toshiba W32T
2. Sony Ericsson W41S
3. Hitachi W32H

Tu-ka:

1. Kyocera TK51
2. Toshiba TT51
3. Kyocera TK41

Vodafone:

1. Toshiba V502T
2. Toshiba 803T
3. Sharp 703SH

Notice anything? They're all Japanese brands and none of the the top 3 global handset manufacturers, Nokia, Motorola or Samsung, are represented. What does this mean? Is Japan is a hard nut to crack or are the manufactuers just not designing phones that Japanese consumers want? Or both?