In Russian, a soft sign must go at the end of adverbs after the letters 'ж', 'ч', 'ш', 'щ'
There are only three exceptions!
One of the fundamental rules of the Russian language states that a soft sign ('Ь') is written at the end of adverbs after the sibilants 'ж', 'ч', 'ш', and 'щ'. For example: 'сплошь' ('entirely') or 'наотмашь' ('with a sweeping blow').
However, there are three exceptions: 'уж' ('already'), 'замуж' ('married') and 'невтерпёж' ('unbearable') – and they are very easy to remember in that exact order, as a phrase.
