¶1A jury in the Superior Court found the defendant guilty of unarmed robbery and assault and battery.
¶2The defendant testified at trial. On cross-examination, the prosecutor asked the defendant if he had previously been con*215victed of armed assault with intent to rob. Defense counsel objected, and the judge held a bench conference. The prosecutor stated that he intended to impeach the defendant with convictions of armed assault with intent to rob, illegal possession of a firearm, unlawful carrying of a firearm, and armed robbery while masked. The prosecutor offered to show the judge more recent convictions which were not admissible because the defendant had not been represented by counsel. The judge stated: “No. I don’t have to have that as long as the statute is complied with, and I’m going to overrule the objection of counsel. I’ll give a limiting instruction. It’s the risk the defendant takes. There was no previous motion in limine provided to this Court. I agree that I have a right — I have a duty to come to the side bench and determine whether or not the offenses that are offered fall within the statutory periods. If they do, and being felonies within ten years, once they have been satisfactorily indicated, as based on certified copies . . . .”
¶3We have stated that, in admitting evidence of prior convictions to impeach a defendant, we will review “whether the judge knew he had discretion and exercised it, or believed that his decision was compelled by the statute.” Commonwealth v. Knight, 392 Mass. 192, 195 (1984). See Commonwealth v. Guilfoyle, 396 Mass. 1003, 1004 (1985); Commonwealth v. McFarland, 15 Mass. App. Ct. 948, 949 (1983). See also Commonwealth v. Maguire, 392 Mass. 466, 470 (1984) (appellate courts will review exercise of judge’s discretion). We agree with the reasoning of the Appeals Court in concluding that the judge did not exercise discretion in admitting the prior convictions. From the record, it appears that the judge concluded that he only had to ensure that the prior convictions fell within the statutory periods because the defendant had not made a motion in limine. While a motion in limine will often be the most opportune method of seeking a ruling on the admissibility of prior convictions,
¶4Judgment reversed.
¶5Verdict set aside.
¶6 The conviction of assault and battery was placed on file. The defendant appeals only from the conviction of unarmed robbery.
¶7 In this case, the defendant’s interests would have been better served by a motion in limine. As it was, the defendant interposed objection only after a leading question by the prosecutor had brought the subject of prior convictions to the jury’s attention.