Thinkpad KT-1255 Bluetooth Keyboard Pairing

I don’t know why press the power key over 3 seconds cannot make this keyboard enter pairing mode.
LED will flash quickly around 2 second then blinked

So there is another option can make it enter pairing mode, it’s keyboard’s NFC function

Unlock SmartPhone, and use SmartPhone NFC zone to touch the keyboard’s NFC zone (close to ThinkPad Logo),
then keyboard will enter pairing mode.
Done.