How do you use “Akeru” and “Hiraku”?

あける means to remove a barrier or cover, like "open a lid" or "open a bag". ひらく refers to opening something layered or folded, like "open a package" or "open an umbrella", but not removing barriers. You can say 「ふたをあける」because a lid blocks something, but not 「ふたをひらく」since a lid isn't layered. Both あける and ひらく work for windows: 「まどをあける」removes barriers, and 「まどをひらく」opens the window connected to the frame. Similarly, use 「ふたをひらく」for flip-top caps as they're connected to the bottle.