Chinese famille verte charger. what does the mark on the bottom mean? Any idea how old?

It's the Dhvaja, one of the eight Buddhist Ashtamangala - there are more of them around the margin of the plate. It is also a good sign it is pre the Cultural Revolution as the Republic was not big on religion.

 

so perhaps early 20th century? Its chinese or maybe Tibetan?

 

The Buddhist symbols were used on Chinese and Japanese (also Indian) items, I think it probably is Chinese but does certainly have some Japanese stylistic traits. Probably late 19th I would think.

 

And Himalayan, where they originated. But this looks Chinese to me too.

 

It looks liek a famille verte Kangxi plate. The double blue line indicate it is presenting itself as chinese, so the plate is not saying it is japanese, and the Kangxi Mark on the back is common to be sometimes a leaf or a rabbit or many other designs. If you google kangxi backmarks you can find a inventory of all the kangxi backmarks.

I think the symbol means a pair of Books. You can find it on page 141 of this online book.

https://archive.org/details/handbookofmarkso00burtuoft/page/138/mode/2up

https://archive.org/details/chineseporcelain00xian/page/n117/mode/2up