was, what, war
Something strange happens when we add 'w' to 'a'. Take a look at these words and listen to the pronunciation:
bat //, cat // --- what //
catch //, match // --- watch //
bar //, car // --- war //
w(h)a-
/wɒ/ want, was, what, wander
/wɔː/ water, walk, wall
war-
/wɔː/ war, ward, warm, warn
/weə/ ware (= w+are, not war+e)
This also happens when there is /w/ in the sound, even if it is not in the spelling:
qua-
/kwɒ/ quality, quantity, qualify, quantify
quar-
/kwɔː/ quarter
squa-
/skwɒ/ squad, squat
squar-
/skweə/ square (= squ+are, not squar+e)