Could this also mean "which bag is from you" - as in "which of the bags is the one that you gave me"?
What's wrong with "which is your bag?"
In english you would say "which one is your bag?"
Fortunately for me Tasche/Taschen is bag/bags in German.
is this the way one says "yours" in netherlands? "van" and then the genetive pronoun?
Yes, but although not often used, 'de jouwe' would also be correct
Man it's hard to dal with Tas considering its meaning in french
How do I know when to use "jou" and "jouw"? Don't they both mean 'you/yours'?
Actually "you" and "your".
I see you (ik zie jou). (jou = pronoun)
I see your bag (ik zie jouw tas). (jouw = possessive pronoun)
The bag is yours (de tas is van jou). (jou = pronoun after preposition 'van').
Thank you vam1980. Now I will remember!