title_body: What notation do constructed sign languages use? What notation do constructed sign languages use?
  Many well-known big sign languages (such as ASL) have their own form of notation, but that notation is very specific and may not be able to express a sign in other sign languages. For example, ASL school is 
  
  OpenB@Palm-PalmDown-OpenB@CenterChesthigh-PalmUp Contact Contact
  
  
  but some constructed sign language X might require signals that don't appear in ASL, like 'touch your elbow with the thumb of your non-dominant hand'. The notation could be extended but would be complicating it. Language X thus requires its own system for its own signs or an 'international' one in analogy with the International Phonetic Alphabet.
  
  What are the notations commonly used by constructed sign languages?
  Which sign languages use them?
upvoted_answer: There are very few constructed sign languages. On the subreddit, we sometimes get questions about whether anyone has made any, which usually don’t get many replies. This one here has some examples given, and also links a website which has basically the answer to your actual question: 
  
  SLIPA is an attempt by David Peterson to fill the lack of sign language transcription systems. However, due to it being ASCII-compliant, it ends up rather unweildy and I’ve never seen it employed in actuality. Nevertheless, the website provides important information that could be useful for you to derive your own system tailored to your language, and to use as a reference for comparing your own notation to.