In recent times, Seon Masters Gyeongheo Seong-u (1846-1912) and Yongseong Chinjong (1864-1940) greatly promoted the Ganhwa Seon style. Gyeongheo succeeded to the Dharma of Seon Master Yong-am Hye-eon. ... Seon Master Yeongseong succeeded to the Dharma lineage of Hwanseong Jian.
And the look at this mail written in defence of Samu Sunim's authenticity:
Unlike the Japanese Rinzai Zen tradition, which sometimes boasts of “unbroken transmission,” there are many Korean Seon (Zen) Masters who became enlightened without a teacher. The most famous among them were Gyeongheo (1849-1912) and Seongcheol (1912-1993). Gyeongheo revitalized Korean Seon Buddhism toward the end of the 19th century, while Seongcheol served as the Supreme Ancestor of the Jogye Order from 1981 until he passed away. Yongseong (1864-1940), Samu Sunim’s Grand Master, was another one who attained enlightenment without a teacher.
Well, it is not unlike at all when Hakuin's transmission is very much in doubt, to say the least, but that has already been looked into by others. Gyeongheo is a different case. This is from a book published just last year:
Following his spiritual awakening, Kyŏnghŏ went to the Ch’ŏnjang Temple. Here he received dharma-transmission from the Sŏn Master Yŏngun (b. 1783), an eleventh-generation successor in the direct line of Hyujŏng (1520–1604) also known as Great Master Sŏsan. At age thirty-three, Kyŏnghŏ succeeded Yŏngun as spiritual leader (K. pangjang) of the temple.
(Henrik H. Sørensen: Mirror of Emptiness - The Life and Times of the Sŏn Master Kyŏnghŏ Sŏngu; in Makers of Modern Korean Buddhism, SUNY Press, Albany, USA. 2010. p. 133)
Let's think here a bit. Yeongwol Bongyul (영월봉율/永月奉律, 1738-1823; source), that is Yŏngun, was already dead when Gyeongheo was born (1846/1849, date unclear). But OK, the official website says the same, so Sørensen could have been mislead by whatever sources he were using:
In spring of the next year, he moved to Cheonjangam Hermitage in Mt. Yeonamsan, and continued the practice which succeeds enlightenment. He said he was continuing the lineage of Yongam who was a successor of the Cheongheo and Hwanseong.
It is more interesting that in transmission lineages (see here and here) it is Manhwa Boseon (만화 보선, 萬化普善, d.u.) identified as the preceding 74th patriarch and Yeongwol is the 73rd. Makes more sense, although from the different biographies I've read it appears that Manhwa was only Gyeongheo's ordination master at best. It is even more fascinating what the biography in his collected writings say:
[quoting Gyeongheo:]"Although my enlightenment is not complete and has not been acknowledged by a master, what I have been trying all my life is to firmly establish what the duty of an ascetic is. I am already old and in the future my disciples should transmit the law to Elder Yongam, to establish a clear lineage of the law that I received from my master Manhwa.
[biographer continues:]In obeyance of the master's will, we found the origination of transmission that the preceptor succeeded the law of Yongam and Hye-eon, and it is transmitted from Hye-eon to Geumho and Byeolcheom, from Byeolcheom to Yulbong and Cheonggo, and from Cheonggo to Cheongbong and Geo-ae, and from Geo-ae to Ho-am and Chejeong, and from Cheongheo to Pyeonyang, and from Pyeonyang to Pungdam, from Pungdam to Wondam, and from Wondam to Hwanseong. Thus, Preceptor Gyeongheo is the 12th legitimate disciple of Cheongheo and the 7th legitimate disciple of Hwanseong."
The translator looks confused about the names a bit (the "and" between names is unnecessary) but that's a secondary thing. What Gyeongheo explicitly says is that there was nobody who gave him any kind of dharma-transmission. But then in the next paragraph a lineage is established. Note that such a lineage was created by the disciples.
There are two other famous masters mentioned in Bopkyong's letter, although they don't have such flourishing descendants as Gyeongheo. Nevertheless, here are two essays to read about them:
"Bodhidharma said that those who sought Buddhas and patriarchs apart from the mind of sentient beings were “heavenly demons and heretics” (cheonma oedo). . . . There are people who seek Heaven (cheon) apart from mind-nature (simseong) and worship it, and there are those who say that Heaven is creating [something], but they are all deluded."
A Monk of Mukti and Karma: The Life and Thought of Baek Yongseong by Huh Woosung (download file, can be opened by Adobe Reader)
"Venerable Songchul also emphasized the need for this kind of certification by an authentic Master. That is one of the reasons why Venerable Songchul criticized Chinul's Seon. The Jogye Order linage has always been transmitted by formal recognition received from a Seon master. Venerable Songchul insists that Chinul had no such recognition. But there is also no evidence that Songchul had certification by a Seon master."
The real question is, however, what do we make of it? Certainly I'm not questioning the greatness of the above masters who have played such enormous roles in developing modern Korean Buddhism. The problem is not with them but the way dharma-transmission is understood. Once it was developed by certain Chinese monks to establish their positions in monastic hierarchy. But what use does it have now? It is obviously not a proof of one's enlightenment or anything like that. It doesn't guarantee anything except for a weak basis for religious superiority. Then why are modern Zen people hung up on it so much?