This ease is a sequel to our recent Marshall decision 1 wherein we reasserted a procedural standard to be observed in connection with recidivist sentences under D.C. Code § 22-3204. Each appellant was indicted on a charge of carrying an unlicensed pistol in violation of Section 3204 and, at a joint trial, each was convicted of that offense by a jury. Thereafter, the trial judge imposed prison sentences of three to ten years on appellant Clemons and two to six years on appellant Blyther. On these consolidated appeals, we confront attacks by both appellants on their convictions, and by Clemons on his sentence as well.2 We affirm the convictions but remand for a resentencing of Clemons.
The only problem requiring extended discussion is posed by the series of events culminating in Clemons’ sentence.3 After the jury returned its verdicts, the Government served on Clemons’ trial counsel,4 and filed with the court, an information asserting that he had been convicted of robbery in 1958.5 That conviction, the information continued, laid the foundation for a greater sentence — to confinement for as long as ten years — than Clemons’ pistol-carrying conviction would otherwise have authorized. Indubitably the Government’s legal theory was correct if its factual premise was accurate. Penalties for violations of Section 3204 may always extend to a $1,000 fine or one year’s imprisonment or both, but may range up*207ward to imprisonment for ten years for violators previously convicted in the District of Columbia of the same offense or of a felony either in the District or elsewhere.6
At Clemons’ sentencing session, however, there was neither proof of nor inquiry as to the alleged robbery conviction. Indeed, no reference whatever was made to the Government’s information or to the averments it contained. So it was, as in Marshall, that we decided to consider en banc the validity of the procedure leading up to' Clemons’ ten-year sentence.
Marshall reaffirms our earlier Jackson holding7 that proof of the prior conviction in the presence of the accused is prerequisite to imposition of any Section 3204 sentence in excess of a year. Clemons’ situation, however, diverges somewhat from Marshall’s. The Government, we reiterate, charged Clemons’ conviction of robbery in 1958; his application to this court for release pending appeal, we see, concedes a 1957 robbery conviction. Nowhere along the line has there been any suggestion that there was any infirmity in the conviction — assuming Clemons and the Government refer to the same one — that might serve to eliminate it as the predicate for an enhanced sentence. Under these circumstances, then, one may wonder as to whether the absence of actual proof of the robbery conviction was harmless error, warranting the conclusion that Clemons’ sentence should be left as it is.
In Oyler v. Boles,8 the Supreme Court examined two superficially similar situations. In separate instances, after an information alleging past felony convictions had been filed, each petitioner, in open court accompanied by his counsel, admitted that he was the party who had been so convicted, without objection to the convictions. The Court held that these admissions rendered unnecessary any further inquiry.9 And in one of our own cases, Kendrick v. United States,10 after the accused had been convicted under Section 3204, the Government failed to adduce proof of two prior felony convictions charged by information as the basis for an increased sentence. It was held that this omission was set for naught by the accused’s acknowledgment, on his cross-examination at the trial, of the same two convictions.11
We think, however, that the case before us ushers in difficulties which were not encountered in Oyler or Kendrick. The concession in Clemons’ bail application — speaking to a 1957, not a 1958, conviction — otherwise lacks precision in its reference, and we can only assume, without knowing to a certainty, that it pertains to the robbery conviction specified in the Government’s information. If, on the other hand, we do not make the assumption, we face the question whether demon’s recidivist sentence can be rested upon a prior conviction not charged by the Government in its information.12 Moreover, the bail application containing the concession was prepared and signed, not by Clemons personally, but by his counsel. While counsel properly included this item of information for consideration in connection with the application, the question arises as to whether, absent proof of his client’s authorization, counsel’s action could also operate as “a waiver of [or] a substitute for actual proof of a fact *208which so drastically increases the maximum imprisonment.” 13
Even more importantly, identity of the accused as the previously-convicted party is by no means the only question open to debate in proceedings to increase punishment under recidivist provisions. Not only the existence of the prior conviction but also its character,14 its continuing efficacy15 and its constitutional validity16 are among the inquiries appropriate. There is indication, too, that any defect which exposes the prior conviction to collateral attack may be asserted defensively in the recidivist proceeding.17 We do not now so decide, but we do point out that we have no way of knowing whether any such infirmity could have been urged successfully had the Government proved a robbery conviction before sentence was pronounced. In sum, counsel’s concession of a past conviction for bail purposes is not tantamount to a concession of its serviceability for purposes of a recidivist sentence.18
We are mindful, too, that to accept the mention in the bail application of a robbery conviction as a substitute for proof of the conviction at sentencing would deprive Clemons of a valuable opportunity we identified in Marshall. “When the proof is introduced in the presence of the defendant,” we said, “meaningful opportunity is afforded, which might otherwise be unavailable, to enable the accused in the exercise of his right of allocution to advance any reasons he might have why the court should not enlarge the sentence because of his past record.” 19 And, very significantly for the instant case, we added that “[e]ven when the fact of conviction is not disputable he may adduce whatever he deems appropriate for the judge to consider in connection with it.” 20
These difficulties persuade us, in deciding this case, to revert to fundamentals. Our context is a proceeding21 enabling the sentencing judge to elevate *209a misdemeanor to felony status,22 and to inflict additional punishment if the accused has suffered either of two types of prior conviction.23 We have no doubt that the proceeding is criminal in character,24 and as much as any other that paves the way to prison. We have no doubt, either, that the accused recidivist, similarly to an accused first offender, must be sheltered by suitable safeguards against an improper sentence.
The statute under which Clemons was committed for a maximum of ten years is completely silent on the procedural events that must forerun an enhanced sentence. But Congress, in plain language, set the conditions precedent to any gun-carrying sentence of imprisonment more than a year in duration. In a decidedly criminal proceeding wherein punishment may be multiplied — here by a factor of ten — nothing so vital as the existence of the conditions authorizing a stepped-up sentence should be left to surmise. And perhaps the procedural standard least dispensible to any just ascertainment of the essential substantive elements of a sentence for illegal pistol-toting is proof adequate to support affirmative judicial determinations on that score.25 We recognize, of course, that the accused’s admissions may sometimes rise to a level of certainty so high as to obviate the need for particular items of formal proof by the Government. We conclude, however, that the bare reference in Clemons’ bail motion to an otherwise unelucidated past robbery conviction cannot remedy the total absence of proof here.
We affirm the judgments appealed from to the extent that they convict appellants of the offense of carrying an unlicensed pistol. We vacate Clemons’ sentence and remand his case for a re-sentencing. The sentence that may permissibly be imposed upon Clemons must not exceed one year unless the Government introduces evidence, with Clemons and his counsel present, which satisfies the sentencing judge that prior to his Section 3204 offense Clemons had been convicted of a similar violation or a felony.26
. United States v. Marshall, - U.S.App.D.C. -, 440 F.2d 195 (en banc), cert. denied, 400 U.S. 909, 91 S.Ct. 153, 27 L.Ed.2d 148 (1970).
. Blyther does not complain of his sentence. For that reason, and because the record on appeal does not contain a transcript of his sentencing proceeding, we do not consider his sentence.
. Appellants’ challenges to the convictions need be mentioned only briefly. The fact that the indictment charged each with having carried a pistol “openly and concealed” about his person, rather than in the statutory language “openly or concealed,” presents no occasion for reversal. See, e. g., Morrison v. United States, 124 U.S.App.D.C. 330, 331-332, 365 F.2d 521, 522-523 (1966) ; District of Columbia v. Hunt, 82 U.S.App.D.C. 159, 163-164, 163 F.2d 833, 837-838 (1947). Nor, all circumstances considered, especially the voir dire examination of the prospective jurors and the judge’s subsequent instructions to them, do we find such an occasion in the denial of appellants’ motion for a continuance because of publicity regai'ding gun control, the assassination of Senator Robert F. Kennedy and other events concomitant with the trial. We find the evidence legally sufficient to support the jury’s verdicts, Wilson v. United States, 91 U.S.App.D.C. 135, 137, 198 F.2d 299, 300 (1952) ; Brown v. United States, 58 App.D.C. 311, 312, 30 F.2d 474, 475 (1929) ; and, no plain error affecting substantial rights appearing, see F.R.Crim.P. 52(b), we do not pass on Blyther’s previously unraised objections to seizure of the pistols, see Fuller v. United States, 132 U.S.App.D.C. 264, 279-280, 407 F.2d 1199, 1214-1215 (1967), cert. denied, 393 U.S. 1120, 89 S.Ct. 999, 22 L.Ed.2d 125 (1969); to his joint trial with Clemons, see Cupo v. United States, 123 U.S.App.D.C. 324, 327, 359 F.2d 990, 993 (1966) ; or to the trial judge’s instructions to the jury, see F.R.Crim.P. 30; Howard v. United States, 128 U.S.App.D.C. 336, 339, 389 F.2d 287, 290 (1967).
. Neither appellant was represented at trial by his counsel on appeal.
. D.C.Code § 22-2901 (1967), since amended (Supp. I 1968). The offense defined by this section is a felony.
. D.C.Code §§ 22-3204, 22-3215 (1967).
. Jackson v. United States, 95 U.S.App.D.C. 328, 221 F.2d 883 (1955).
. 368 U.S. 448, 82 S.Ct. 501, 7 L.Ed.2d 446 (1962).
. Id. at 453, 82 S.Ct. at 501.
. 99 U.S.App.D.C. 173, 238 F.2d 34 (1956).
. Id. at 176, 238 F.2d at 37.
. See Cole v. Arkansas, 333 U.S. 196, 68 S.Ct. 514, 92 L.Ed. 644 (1948). Cf. Williams v. New York, 337 U.S. 241, 69 S.Ct. 1079, 93 L.Ed. 1337 (1949), which did not involve greater punishment simply by reason of recidivism.
. Jackson v. United States, supra note 7, 95 U.S.App.D.C. at 330, 221, F.2d at 885. “Such proof,” we declared, “which so largely shapes the sentence should be introduced in the defendant’s presence, just as the sentence itself must be pronounced in his presence.” Id.
. See text supra at note 6. Of moment in particular cases may be the question whether the prior conviction was for a felony or a misdemeanor, more especially where it occurred in another jurisdiction.
. See, e. g., 18 U.S.C. § 5021(a) (1964), as to the effect of which we express no opinion. Cf. Tatum v. United States, 114 U.S.App.D.C. 51, 53 n. 2, 310 F.2d 854, 856 n. 2 (1962).
. Burgett v. Texas, 389 U.S. 109, 114-115, 88 S.Ct. 258, 19 L.Ed.2d 319 (1967) ; Chewning v. Cunningham, 368 U.S. 443, 445-447, 82 S.Ct. 498, 7 L.Ed.2d 442 (1962). See also Reynolds v. Cochran, 365 U.S. 525, 531, 81 S.Ct. 723, 5 L.Ed.2d 754 (1961).
. See Burgett v. Texas, supra note 16, 389 U.S. at 114-115, 88 S.Ct. 258; Oyler v. Boles, supra note 8, 368 U.S. at 453-454, 82 S.Ct. 501; Chewning v. Cunningham, supra note 16, 368 U.S. at 445-447, 82 S.Ct. 498; Reynolds v. Cochran, supra note 16, 365 U.S. at 532, 81 S.Ct. 723.
. In Oyler v. Boles, supra note 8, 368 U.S. at 454, 82 S.Ct. 501, 505, by the Court’s characterization, “the record clearly shows that both petitioners personally and through their lawyers conceded the applicability of the law’s sanctions to the circumstances of their cases.” And in Kendrick v. United States, supra note 10, 99 U.S.App.D.C. at 176, 238 F.2d at 37, “[i]n [the] circumstances the production of evidence after verdict and before sentence to show [the] previous convictions would have been an idle formality.”
. United States v. Marshall, supra note 1, at 206, 440 F.2d at 198.
. Id. at 206, 440 F.2d 199.
. For major classifications of the types of proceedings in vogue in the United States and England, see Note, Recidivist Procedures, 40 N.Y.U.L.Rev. 332 (1965) ; Note, The Pleading and Proof of Prior Convictions in Habitual Criminal Prosecutions, 33 N.Y.U.L.Rev. 210 (1958). In practice, the statute under which Clemons’ sentence was increased is treated as prescribing a proceeding supplementary to the trial of the underlying offense. See Kendrick v. United States, supra note *20910, 99 U.S.App.D.C. at 176, 238 F.2d at 37; Jackson v. United States, supra note 7, 95 U.S.App.D.C. at 328, 221 F.2d at 883.
. See Burrell v. United States, 223 A.2d 377, 378 (D.C.App.1966). See also Lawrence v. United States, 224 A.2d 306, 307-308 (D.C.App.1966).
. See text supra at note 6.
. See Chewning v. Cunningham, supra note 16, 368 U.S. at 445, 82 S.Ct. 498; People v. Reese, 258 N.Y. 89, 179 N.E. 305, 309, 79 A.L.R. 1329 (1932) ; State v. Durham, 177 Or. 574, 164 P.2d 448, 450, 162 A.L.R. 422 (1945). This is so notwithstanding the accepted view that recidivist statutes do not create separate offenses, but only enhance the punishment on account of prior conviction. See Chandler v. Fretag, 348 U.S. 3, 7, 75 S.Ct. 1, 99 L.Ed. 4 (1954) ; Graham v. West Virginia, 224 U.S. 616, 623-624, 32 S.Ct. 583, 56 L.Ed. 917 (1912) ; Jackson v. United States, supra note 7, 95 U.S.App.D.C. at 330, 221 F.2d at 885.
. Other procedural standards include reasonable notice of the recidivist charge, Oyler v. Boles, supra note 8, 368 U.S. at 452, 82 S.Ct. 501; opportunity to be heard, id.; Chandler v. Fretag, supra note 24, 348 U.S. at 8, 75 S.Ct. 1; and right to counsel, Chewning v. Cunningham, supra note 16; Reynolds v. Cochran, supra note 16; Chandler v. Fretag, supra note 24.
. Marshall requires rejection of Clemons’ contention that to do so would put him twice in jeopardy. United States v. Marshall, supra note 1, at 206, 440 F.2d at 199 n. 10. We dispose of Clemons’ final contention on the basis of our holding in Kendrick, to which we adhere, that § 3204 does not deny the equal protection of the laws. Kendrick v. United States, supra note 10, 99 U.S.App.D.C. at 175-176, 238 F.2d at 36-37.