Conditional: い-Adjective ければ JLPT N4
The conditional 'if it is (adjective)' form.
Formation
Drop the final い and add ければ: 高い -> 高ければ. Irregular: いい -> よければ.
Explanation
い-adjectives take the same ば-conditional as verbs, replacing い with ければ (安ければ買う, 'if it's cheap, I'll buy it').