▁Qu an ▁h ọ ▁() ▁singing ▁is ▁a ▁Vietnam ese ▁folk ▁music ▁style ▁character ized ▁both ▁by ▁its ▁anti ph onal ▁nature , ▁with ▁altern ating ▁groups ▁of ▁female ▁and ▁male ▁sing ers ▁issu ing ▁musical ▁challeng es ▁and ▁responses , ▁and ▁by ▁the ▁fact ▁that ▁most ▁of ▁the ▁songs ▁in ▁the ▁re per toire ▁deal ▁with ▁topics ▁of ▁love ▁and ▁sentiment ality ▁as ▁experienced ▁by ▁young ▁adult s . ▁ ▁Qu an ▁ho ▁is ▁recogn ised ▁as ▁the ▁Int ang ible ▁Cultural ▁Heritage ▁by ▁the ▁UN ES CO ▁in ▁ 2 0 0 9 . ▁ ▁The ▁quan ▁h ọ ▁style ▁origin ated ▁in ▁what ▁is ▁now ▁B ắ c ▁Nin h ▁Province ▁and ▁was ▁first ▁recorded ▁in ▁the ▁ 1 3 th ▁century , ▁and ▁has ▁tradition ally ▁been ▁associated ▁with ▁the ▁spring ▁festiv als ▁that ▁follow ▁the ▁celebr ation ▁of ▁T ế t ▁( the ▁Vietnam ese ▁New ▁Year ). ▁Histor ically , ▁the ▁singing ▁began ▁on ▁the ▁evening ▁before ▁the ▁festival , ▁but ▁today ▁it ▁is ▁much ▁more ▁common ▁for ▁the ▁singing ▁to ▁occur ▁on ▁the ▁main ▁day ▁of ▁the ▁festival . ▁In ▁general , ▁an ▁initial ▁" ch allenge ▁phrase " ▁( c â u ▁ra ) ▁from ▁the ▁known ▁body ▁of ▁songs ▁is ▁s ung ▁by ▁a ▁pair ▁of ▁female ▁sing ers , ▁following ▁which ▁a ▁pair ▁of ▁male ▁sing ers ▁will ▁respond ▁by ▁selecting ▁and ▁singing ▁a ▁" match ing ▁phrase " ▁( c â u ▁ đ ố i ), ▁which ▁must ▁repeat ▁the ▁mel