Is it common for the HSK to include erhua variants instead of non-erhua? My understanding is that erhua variants are most common in Beijing. Should I focus my vocabulary on learning erhua variants?
According to the official HSK1 vocabulary list published by Hanban in September 2012, erhua variants may occur in the test since they are included in the vocabulary list.
So you should focus on both non-erhua and erhua variants of the words.
For what it's worth, I feel the HSK committee here is being frankly unreasonable with all the 儿化 variants it lists:
- 墨水儿 (seriously???)
are all things that you'd never hear in a news broadcast, while 墨水 etc would be, but are not listed in the HSK vocab. On the other hand, they list as single-character words things that I'd never hear without 子: 梨子, 桃子 (are the only two I can think of now).