US Keyboard for Japanese Ubuntu at 2019

US Keyboard setting for Japanese Ubuntu is bit difficult.

Simplest way is below.

0. requirement : Mozc setup completed.
1. add input source US by Ubuntu general setting.
2. and move to top position of input source
3. open IME setting by top right Icon> tool > properties
4. open key setting > edit
5. change Hankaku/Zenkaku to Ctrl Space and so on
6. and save(click OK)
7. reboot(messages tell no need to reboot, but not work well for me, so if it is not work, try reboot)
8. Ctrl Space can change Direct or Japanese input mode.

Enjoy Ubuntu!