Buying liability insurance for a car

Japan resident, bought a car from auction. Car and paperwork just delivered.

I have read this guide Buying a Used Car Privately in Japan | Tokyo Cheapo

My question is regard step 4, of the liability insurance. I assume it’s referring to jibaiseki hoken. My new vehicle has 5 months of Shaken on it. If you need the compulsory liability insurance to get a shaken, and the shaken stays with the vehicle, does the insurance stay with the vehicle too… hence is this step necessary (in this example).

In the paperwork I can see the shaken and insurance (date still valid).