When did soviet capsules begin using retropropulsion immediately before landing?

Question

Wikipedia's Yuri Gagarin says:

At about 23,000 feet (7,000 m), Gagarin ejected from the descending capsule as planned and landed using a parachute.

and the section Vostok_programme; Vostok 3KA says:

After one orbit, the descent module successfully re-entered the atmosphere, the mannequin was safely ejected, and the dog and other specimens landed separately in the descent module by parachute.

I assume the ejection of the mannequin was a simulation of an astronaut parachuting rather than remaining in the capsule as it landed.

However, this answer to the question Soyuz landing ground detection says:

Earlier Voskhod models used a retractable metal probe, but it was unreliable, especially in windy conditions. So in Soyuz, as the other answers have pointed out, a gamma-ray source is pointed at the ground and the backscatter is measured. The instrument ("Kaktus"), was developed in the early 60s.

That suggests that retropropulsion may have been used during Vostok.

Question: When exactly did soviet capsules begin using retropropulsion immediately before landing? Which spaceflight mission was the first to use it successfully?

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Related:

• How does a gamma ray altimeter work? What kind of sensor is used?
• How does New Shepard Crew Capsule sense proximity to trigger retropropulsion just before impact?

Answer 1

According to Wikipedia, Voskhod's requirement to put multiple crew members in a sphere the same size as Vostok forced elimination of the earlier spacecraft's ejection seat (and in the case of Voskhod 1, eliminated pressure suits as well!) and drove the new landing technique:

The lack of ejection seats meant that the Voskhod crew would return to Earth inside their spacecraft unlike the Vostok cosmonauts who ejected and parachuted down separately. Because of this, a new landing system was developed, which added a small solid-fuel rocket to the parachute lines. It fired as the descent module neared touchdown, providing a softer landing.

Voskhod was a fairly short program; I believe the first landing-retropropulsion flight would have been the uncrewed Kosmos 47 mission on 6 October 1964, being the sole test flight before the 3-crew Voskhod 1 flight six days later.