No, no! Не! ВЪВ-използва се пред думи започващи с буквата В или Ф. За по-лесен изговор и четене. В-използва се пред всички останали, незапочващи с буквата В или Ф. В София. В хотела. В метрото. В трамвая. В залата. В университета. В гората. Във влака. Във вагона. Във Варна. Във Видин. Във Витлеем. Във фризера. Във фабриката. Във вазата. Във фурната.

It is actually really easy. "Vav" is used when the next word start with "v'' or "f" (в/ф) , but when we talk we often say vav infront words starting with other letters, just to emphasize what we are saying. But for the writing there is just one rule! It`s like the English - an apple, an hour, a book. vav vazata във вазата in the vase v restoranta в ресторанта in the restaurant If you need help i offer as well classes in Bulgarian! Wish you luck!

Martin's already explained well about the rule that applies on how to write "в/във" .... in addition: when it comes to SPEAKING, since 'в' technically is not a word (without a vowel it's not even a syllable) and can not be pronounced alone, usually it is pronounced joined to the next word. However, if you want to stress on this preposition, or just want to articulate clearly or slowly - 'във' is the only right way to say it. 'Във' is also the only way to say it when the following word begins with "в". With the preposition "с/със"- it is the same.