One of the interesting features of the CB125E is the keyswitch shutter – it’s an anti-vandalism and anti-theft device to prevent someone from jamming something into the lock, or trying to pick it. Look to the left of the “usual” key hole and you’ll see it:
There’s an extra bump on the Honda key to match the shutter’s switch:
Looking at it end-on:
Put them together…
Turn it to “shut” and voila, the shutter is closed:
Turn the key back and it’ll open again. Pretty useful if you leave your bike anywhere that dubious passers-by can get at it.