| K-401 | Recognises an ambiguous node label | Oskus |
| K-402 | Recognises a node with an unclear boundary and no scope note | Oskus |
| K-403 | Recognises overlapping sibling nodes without reciprocal scope notes | Oskus |
| K-404 | Recognises a meaning change without a history note | Oskus |
| K-405 | Recognises a node without warrant | Oskus |
| K-406 | Recognises inconsistent node label forms | Oskus |
| K-407 | Recognises an abbreviation, jargon or system name as a node label | Oskus |
| K-408 | Recognises a compound node combining two characteristics | Oskus |
| K-409 | Recognises siblings divided by mixed characteristics | Oskus |
| K-410 | Recognises a synonym kept as a separate node | Oskus |
| K-411 | Recognises a link failing the all-and-some test | Oskus |
| K-412 | Recognises an instance placed as a concept node | Oskus |
| K-413 | Recognises a part-of link in a kind-of hierarchy | Oskus |
| K-414 | Recognises an unjustified polyhierarchy | Oskus |
| K-415 | Recognises an associative relationship shown as a hierarchy | Oskus |
| K-416 | Recognises non-reciprocal hierarchy links | Oskus |
| K-417 | Recognises uneven levels of specificity among siblings | Oskus |
| K-418 | Recognises a home-grown copy of an existing vocabulary | Oskus |
| K-423 | Recognises a taxonomy node deleted while data still refers to it | Oskus |
| K-424 | Recognises a node code reused for a different concept | Oskus |
| K-420 | Recognises a structural error in a taxonomy hierarchy | Oskus |
| K-451 | Explains hierarchical relations and the all-and-some test | Teadmine |
| K-452 | Explains scope notes and history notes | Teadmine |
| K-453 | Explains warrant for vocabulary terms | Teadmine |
| K-454 | Explains label form conventions for vocabularies | Teadmine |
| K-455 | Explains characteristics of division and node labels | Teadmine |
| K-456 | Explains equivalence relations and preferred terms | Teadmine |
| K-457 | Explains associative relations | Teadmine |
| K-458 | Explains reuse of external vocabularies | Teadmine |
| K-421 | Models a role as an association to the party playing it | Oskus |
| K-422 | Derives the broader concept from the head of a definition | Oskus |