1.
with effort, at great pains
Indicating that something required considerable effort or trouble; often implying the effort may be wasted.
2.
specially, expressly
Going out of one's way to do something; taking special trouble.
折角 expresses that effort has been made or an opportunity is special/rare. It often appears in two patterns:
1. EXPRESSING WASTED EFFORT:
折角〜のに (despite taking the trouble to...)
Implies disappointment when effort doesn't pay off.
2. EXPRESSING RARE OPPORTUNITY:
折角の〜だから (since it's such a rare ~)
Encourages making the most of a special chance.
COMMON PATTERNS: