Free dative is traditionally classified as an Obj, in spite of the fact that its kinds differ in their syntactic function (Obj, Adv, AuxO). Since free dative is not determined by a verb or by an adjective, it is commonly used also with intransitive verbs. Its use is motivated semantically.
Six types of free dative can be distinguished:
Dative of contact renders the function of making and maintaining a contact (to vám byla zábava that you-Dat was an entertainment, včera jsem ti nemohl usnout yesterday I you-Dat could not get asleep, on ti byl celý nesvůj he you-Dat was out of his humour). A contact function is expressed also by a dative of interest (kyselina nám začíná reagovat the acid us-Dat begins to react, běží nám osmá minuta the second minute us-Dat runs, neparkujte nám na trávě don't park us-Dat on the lawn).
An emotional dative makes the utterance affective (to je mi pěkný začátek this is me-Dat a good beginning, ty nám tu lenošit nebudeš you us-Dat won't idle away your time here).
A possessive dative is assigned afun Adv (příteli se ztratil pes friend-Dat a dog got lost, v uších mu hučelo ears him-Dat tingled, tetě se zalesknou oči to-aunt eyes glitter, hodinky mi jdou špatně the watch me-Dat doesn't go). Possessive dative can be replaced by a possessive pronoun or adjective: šlápl bratrovi na nohu (he stepped brother-Dat on foot) can be reformulated as šlápl na bratrovu nohu (he stepped on his brother's foot). Cf. Adverbials (and borderline cases).
An adverbial dative of regard is also assigned afun Adv: dětem to přišlo vhod (children-Dat it came in handy), státu tím vznikají škody (state-Dat damages arise due to it). Cf. Adverbials (and borderline cases).
The boundary line between an optional Obj determined by valency and a dative of benefit is often vague. With a dative of benefit, the decision between Obj and Adv is made according to the meaning that can be recognized from the context. For example in Jirka napsal Pavlovi dopis (Jirka wrote a letter to Paul) the word Pavlovi (Paul-Dat) is assigned Obj if the meaning of the sentence is Jirka něco sdělil Pavlovi dopisem (Jirka told something to Paul by means of a letter); it is assigned afun Adv if the meaning is Jirka napsal dopis pro Pavla (místo Pavla) někomu (Jirka wrote a letter in place of Pavel to somebody). If we are not able to distinguish the given meaning, Obj is given priority because it is a valency slot though an optional one. In other cases dative of benefit is assigned afun Adv: natrhala jsem jim hrušky (I picked them-Dat pears). A good help is to try and replace the given form by a prepositional case with the preposition pro (for). Cf. also Object Obj, ObjAtr, AtrObj and Adverbials (and borderline cases).
A dative of subject is always assigned Obj: chce se mi pít (it-wants me-Dat to-drink, I want to drink), nemocnému se dýchá lépe (the patient it-breathes better, the patient breathes better), majorovi se tam sedělo dobře (major-Dat it-sat there well, the major liked to sit there), co je mu? (what is him-Dat, what is the matter with him), bylo jim 17 let (it-was them-Dat 17 years, they were 17 years old); cf. Object Obj, ObjAtr, AtrObj. The following constructions, however, do not include a dative of subject: bylo mi špatně/chladno/do smíchu (it-was me-Dat not-well/cold/to laugh), bude to stranám ku prospěchu (it-will-be parties-Dat to benefit, it will be for the benefit of the parties), je mi to jedno (it-is me-Dat equal, I do not mind), nejbližší je mi asi husitská církev (closest is me-Dat perhaps the hussite church), jeho způsob hry mi byl nejsympatičtější (his way of playing me-Dat was most pleasant). In such sentences dative is assigned afun Adv.