"Bag" in Japanese is かばん(kaban).
Also, I think the benefit of knowing Korean is not that some of their words sound similar. Rather, it's because of the syllabic/moraic nature of their alphabet, which mirrors Japanese hiragana/katakana. Korean grammar is also quite similar to Japanese, but that's unrelated to pronunciation.
I also want to say thanks. I feel somewhat trolled by duolingo for teaching me thinks like 1=ichi, 2=ni, etc. and now they just suddenly switch without having this little "here we show you what you learn now" page. that would have been really helpful instead of being tossed into cold water.
Hey, if you're interested, someone posted this page and it could be helpful even though it has been two years since you asked. ;) https://duolingo.fandom.com/wiki/Japanese_Skill:Counting