Just a day depending on color !!!

I too had a black and a red day here with my Xperia P and realized that the day is an identifier which is different for each color. This identifier contains the digits 1-4, which is why the Xperia also indicates the color properly. Even if man changes this to 0 or 5, this does not help, as the program can be interpreted on the Xperia only 1-4. So you really always buys 2 Tags completely free!

I do not understand Sony here absolutely. The obviously want to sell NFC tags.
When looking at a quasi-unique 48-digit serial number or even alphanumeric identifier would bring to the chips, each could with his cell phone a bucket full of different tags use even when repeating the colors ...

So better buy neutral NFC chip, then describe these profiles itself with one of the software available in the Play Store. Here, Chips recommend with 192 bytes as the "small" Sony only 48 bytes are free, which is insufficient for extensive profiles.

I keep the tags only because I want to play with other programs slightly.