Free visa - 144 hours Shanghai???

I intend to go for a 4-day cruise starting from Shanghai on 18 April 2018 going to Japan and then finish in Shanghai on 22 April 2018.

Here is the program:
Date Port Arrive Depart Activity
18-Apr Baoshan (Shanghai), China 4:45 PM
19-Apr Cruising Cruising
20-Apr Shimonoseki, Japan 8:00 AM 8:00 PM Docked
21-Apr Cruising Cruising
22-Apr Baoshan (Shanghai), China 7:00 AM

I am Bulgarian passport holder and my question is: Can I be granted a free stay of up to 144 hours.

My flight is SOF-DOHA-SHANGHAI /PVG/ - 17 Apr. 2018, then going to cruise on 18 Apr.2018 from Baoshan to Shimonoseki, Japan, back on 22-Apr. morning- Baoshan (Shanghai), then fly SHANGHAI /PVG/ - DOHA - SOF - 22 Apr. 2018 late at night

I hope that you can give me correct and quick answer.