Upon trial by jury the defendant was convicted of unarmed robbery (ORB 163.290). The defendant assigns as error the court’s refusal to allow defense counsel to cross-examine the state’s primary witness about her testimony and conduct two and a half years earlier in a prior unrelated case involving the same defendant. An offer of proof was then made which showed that the witness had testified falsely against defendant and had secreted evidence favorable to him from the police:

“Q The specific facts of this was when Don hit a person who had a gun on him, and Don knocked the gun out of the person’s hand and kicked the person, and he was later charged with assault and battery in the City Court, and you testified that the person who Don was accused of assaulting did not have a weapon, and Don testified that in fact he did have a weapon.

“Do you recall that incident?

“A Yes.

“Q Now, isn’t it true that you admitted after testifying under oath in Albany City Court that this person Don assaulted did not have a gun, isn’t it true that you admitted to a police officer and to a city attorney that you were lying and that in fact that person did have a gun?

“A Yes. That was right during court.

((& 5» & * #

“Q And isn’t it true that you not only knew the person had a gun but in fact you had hidden the gun after the transaction took place?

“A Yes.”

*518 The excluded evidence would have revealed the Mas of the witness toward the defendant. In weighing the testimony of a witness the jury is entitled to know the Mas, if any, that the witness entertains for the defendant. Facts wMch show Mas may properly be elicited on cross-examination. State v. Weston, 102 Or 102, 136, 201 P 1083 (1921). See Houser et al v. Heider et al, 221 Or 7, 24, 350 P2d 422 (1960).

The state concedes① that the trial court’s ruling constitutes reversible error.

Reversed and remanded.