My smartphone finds the NFC function. NFC tools reports that it is a NXP Mifare Plus Tag (ISO 14443-4)
A write test to the tag did not work. Though I never used Mifare Plus tags before, so it could be easily my fault. I need to play somewhat more with this..
Access control just based on the serial number would be a weak protection only.
I also read somewhere before that the phone needs to be changed to China, but I do not even know where to configure a region in Android. I configured the language to German and the location it determines itself...