title_body: What decides where is the break between syllables? I'm getting started with creating a language and I run into trouble when I started using rules I devised for protolanguage (e.g. only open syllables).
  
  However I run into trouble when I tried to apply it to string [epse] which I'd syllabilized as [ep.se] rather than [e.pse]. I'm assuming I did something wrong with sonority hierarchy but I failed to find resources about what exactly.
  
  EDIT: I would prefer generic rules for syllabication but for the Y problem - the rules I set so far is (C)CV syllable where:
  
  
  If there are two consonants exactly one of them is a fricative (s, x or ʂ)
  Fricative must follow plosives, nasals and trills but must precede lateral approximants (l)
upvoted_answer: I think as a general rule, a syllable comprises some combination of the following kinds of one or more of the sound types of your language:  vowel, liquid, consonant.  
  
  You've decided on (C)CV.  And if there are two C then one must be a sibilant and the sibilant must follow a stop. So you can have syllables like sa, ta, tsa  but apparently not sta.  You might then have a words like tasa &amp; satsa &amp; tsatsa.
  
  In English, we'd probably break that into SAT-SA.  Your language will likely differ, because everyone knows that a syllable can't end with a consonant!  So, they'd much more likely break the word thus: SA-TSA!
  
  I would argue that what little you've described of your language and its rules speaks in favour of E-PSE rather than EP-SE.  The only thing you "did wrong" was to apply the English rule rather than the rules that apply to your invented language! The second thing you did wrong was to second guess yourself based on the English rule!