Historical facts that lead to He5 (- from Key Boys, Add4 to He5- ):
Folkie Jin : "Kim Hong-Tak (1944~) was one of the 2 leading figures in the early days of "Group Sound Era", of course with Shin Jung-Hyun(1938~). Kim Hong Tak was guitarist and naturally leader of the group. Here, it seems better to put aside the question " Who was the first?". Because with this question of 'the first' or more properly 'the Origin', the ansters will not is the same according to the questioner's perspectives.
For example, if we take one perspective, in this case that of 'Popularity', it will be the Key Boys of Kim Hong Tak which was followed soon afterwards by the Add4 of Shin Jung-Hyun.
A little remark. This Key Boys is not the 'Later' Key Boys who sang the smash hits like "Let's go to the seashore". or "Memories of the seaside", but the 'Earlier' Keyboys. They played some 'Package shows', under the name of the Lock & Key in the stages of the 8 th U.S army which settled in South Korea. Also they played at some new venues like 'Music listen Rooms', 'Live Music Salons', or the traditional ones like in Cinema.
[Cf. At that time the concert was held frequently in Cinema Houses. It was called as 'Cinema Show].
With these latter acts they were known to general 'Korean' public. They were nicknamed as the 'Beatles of Korea' - At that time this meant more similar to a 'cover band of the Beatles'.. (Cf. Because the stages in 8th Army of U.S. was for the Korean in the forbidden area for the evident reason of security. So generally a Korean group or artist who played there was a totally unknown figure to general Korean public).
In the mid-60s which prevailed by the worldwide phenomenon ' Beatlesmanis', the Key Boys, in molding the archetype of the Rock band (or Rock Group) who 'sing and play' (With the Kkokkirri Brothers, the Fools, the Kim Chies, became the pioneers of a new cultural phenomenon (we may now be able to say that it was the early days of 'Pop culture' in Korea). And here lies one symbolic fact concerning the popular culture in general that 1964-1965, the period of their debuts coincides with that of the birth of the 'Weekly Magazine'. With the time, the members of the Key Boys left the group: some Cha Jung Rak and Cha Do Gyun going to solos, some Yoon Hang Ki joining to the Korean Army's entertainment Unit which was sent to the Viet-Nam War, and finally Kim Hong Tak too. But Kim Hong Tak had launched his career of guitarist in a rock group. It was the He 5.
Precisely speaking, the He5 was not launched by Kim hong Tak. According to the memories of its members, the group was found in the winter of 1967 'the five young guys' all belonged to the Wha-Yange Entertainment Inc. had set up the group together; Han Woong (Rhythm guitar and vocal) issued from the Four Guys, Cho Yong Nam (lead guitar and vocal) from the Shin Jung Hyun and the Jokers, Yu Young Chun (vocal) from the Silver Coins, Han Kwang Soo (Bass) from the Kee Jin Sung's Orchestra. For the connoisseurs, they were all 'top-class' musicians from the leading groups of that time.
And in this period Kim Hong Tak was still in the Key Boys. (Cf. Wha-Yang Entertainment Inc. was one of the enterprises who dealt wht matters concerning the distribution of musicians and entertainers for the 8th Army of USA.- tiwh the Universal, Dae-Young,Dong IL).
The He 5 begins tis gigs at the Seven Club in I-Tae-Won (a small quarter of Seoul which is now well know even internationally for its diverse markets, restaurants and bars mainly for the foreign customers. This quarter was the bassist Han Kwang Soo soon afterwards was a challenge for the He5. Kim Hong Tak was recruited as a lead guitarist (So-called 'first guitarist' at that time) and Cho Yong Nam, the griginal lead guitarist of the band changes his speciality to bass guitar. The joining of Kim Hong Tak not only strengthens the group's musical forces but also gives the occasion to the group of presenting themselves to 'general Korean public'. So ends a 'Boy' period of Key Boys, comes a new era of the 'He'."
"Master Lee -(from Master Lee movies)- doesn’t care that much who the Korean Beatles were, but one thing is for sure: in the 1960s and early 1970s a few boy bands certainly tried to emulate the success of the British band (which certainly was great). The most famous group to do so was undoubtedly the Key Boys (here pictured on their 3rd album released in 1971; K-Apple 27, 1971), but other bands such as He5 were also clearly under the Beatles’ spell. Their ‘Hey Jude’ cover song was included on a compilation album by Kim Inbae (JLS-120377). As the excellent Belgian website “Psyche van het Folk” points out here, however, being nicknamed anything in the 1950s probably implied “by American GIs”, as most of these bands set out on the stages of USO shows first, where there were only few (if any) Koreans among the audience. Compared to other Western bands of the time, Beatles songs were not that often censored, which was probably because the band’s style of performance style was not very erotic, and the lyrics not blatantly critical of militarism, or at least not in the minds of the censors (who probably didn’t consider the song ‘Hey Jude’ to represent an appropriate critique of the inappropriate behaviour of a Japanese woman – Yoko Ono, but it is an amusing idea to think one did). Sookmyung Women’s University’s Gayageum Ensemble have in recent years been quite succesful – they would argue themselves – in bridging the divide between traditional Korean music and popular music. The stale, funless and uncreative way in which they have rendered the songs ‘Let it Be’ and ‘Hey Jude’, however, does not earn them Master Lee’s accolade of “pulp”, but, instead, the antonym “crap”. "
"The Key Boys were a very successful Korean rock group that got their start by playing to American GIs stationed in Korea. Often called the Korean Yardbirds, their music ranged from tepid covers of American songs to fuzzy psych freakouts. Note, this isn’t the same group as the Key Brothers, however some of the members are the same. The Key Boys lasted a span of 8 years (1963-1971) before dissolving into various groups and solo careers (Key Brothers, He6, Guys & Dolls, etc.). During this time they recorded over 8 albums, this one being a compilation of their three albums that they recorded for Universal. Most of the songs on here are more on the poppier side but there are a few nice garage/psych tracks too. The two standout tracks for me are My Love is Distant and A Sailor’s Song. Both have this cool lo-fi/garagey sound that make the drums sound like they were recorded in a tunnel, in addition to the great fuzzy guitar and heavy bass."
which states that "Keyboys in 1963 were a quintet as one of the first of the 'group sounds' category, being active on the US army stage.... "