The people begin to know that Goguryo(高句麗) Dynasty used the name of an era through the discovery and decoding of the Hotae King's tombstone. By the reason of that Hotae King was named as the Great King of Yung Lag (永樂) on his tombstone, everybody decided that Yung Lag began to be used from accession to the throne of Hotae King. On his tombstone, the first year of Yung Lag was recorded as the year of Sinmyo(辛卯), therefore it was written as the year of Sinmyo that Hotae King acceded the throne on the current chronological table. Besides the year of Hotae Kong's death was recorded as the year of Yimja(壬子, 412) and the accession to the throne of Jang Su King(長壽王) was recorded as the year of Gechuk(癸丑, 413) on the present chronological table. When we see Goguryo chapter of Samgugsagi(三國史記) from the begining to the end, we can see the record that the death of previous King and the thronement of present King was accomplished at same year. On this principle, the current chronological table can't escape the blame to make the year of the accession to the throne and the death of Hotae King wrongly. 'The record of the period of Hotae King in Goguryo chapter and the Goguryo chronological table of Samgugsagi make clear the year of the accession to the throne(392) and the death of Hotae King(413), the current chronological table's wrong originated in which the people didn't distinguish or didn't criticize and believed blindly the record of the tombstone of Hotae King. According to the present writer's opinion, the year of Sinmyo comes under the first year of Yung Lag, but Hotae King acceded to throne on the year of Yim Ja(壬子). The people were concerned about Yung Lag, judged for Hotae King to ascend the throne in the first year of Yung Lag. The present writer think this judgement is very hasty. The present writer think that from the year of Sinmyo, Dam Dug(談德, Hotae King's name) acted for Gogugyang King who was owing to some trouble and took care of the war to Baegje(百濟) and Wae(倭) with the excellent tactics personally, as the result he made Goguryo as a very powerful military nation, therefore the people of Goguryo counted the first year of Yung Lag from the year of Sinmyo and grasped the year of Sinmyo as the first year of Yung Lag. We must think that the record of the year of Sinmyo is a valid evidence which Hotae King as a person of the crown prince defeated Wae's troop who invaded the peninsular of Korea. Baegje connected with Wae and turned Silla(新羅) into the officials and the people in the fifth year of Yung Lag(the fourth year of Hotae King's enthronement, 395), therefore Hotae King conquered Baegje in the sixth year of Yung Lag(396) and occupied 58 castles. It is the outline of the record in the sixth year of Hotae King's tombstone. According to the present writer's investigation, it is not at once in the sixth year of Yung Lag that the troop of Goguryo occupied these castles from the first year of Hotae King's entronement(the second year of Yung Lag) to the fourth year of his enthronement(the fifth year of Yung Lag). According to record of the fifth year of his tombstone, we can see a part that Baegje and Silla originally paid tribute to Goguryo as the officials and the people, when compared with Samgugsagi(三國史記), this part is quite hackeneyed expression that showes the self-respect of Goguryo, the record that the troop of Goguryo occupied 58 castles in the sixth year of Yung Lag is not worth deliberation as fact. The location of 58 castles is not yet known, one of these castles is Gomoru castle(古牟婁城), it is recorded in Goguryo monument of Jung Won(中原高句麗碑). In connection with the location of Gomoru castle, there are three opinions, those are old castle of Eum Sung(陰城, Chung-cheong north province), castle of Dug San(德山, Chung-cheong south province) and the mount fortress wall of Gomori(古牟里, Pocheon County). According to the present writer's documentary investigation, field investigation doeumentary approach, there is possibility that the mount fortress wall will be the Gomoru castle. Yet now the name of a place which is named Moru(牟婁) in Pocheon district are numerous. It is common sense that the name of a place is connected with the historical origin. Originally Pocheon district was the land such as a corner where was the northeast district of Ma Han(馬韓). Onjo King(溫祚王) of Baegje was ceded the territory of 100 Li(里) by the King of Ma Han on condition on that he protects the invasion of Malgal(靺鞨), therefore this land was named as a corner(Moru) at Baegje period also. Such as we see Moru(牟婁), Moro(牟婁), Gomoru(古牟婁), Gumoro(舊模盧), Gagmoro(各模盧) on the tombstone of Hotae King, the name of each castle to be written as the letter which was named 'Moru' was originated in Moru(corner), that is the present writer's opinion. In view point of the topography, the uphill pass of Bidugjae(비득재) where is situated the east of Gomoru castle was very important military trappic road that attached Chul Won(鐵原) to the north coast of Han River(漢江), therefore it is hard to exclude the possibility that the troop of Goguryo utilized this root sufficiently in connection with the invasion of Hotae King to Baegje. Historically the uphill pass of Bidugjae was utilized as the barrier to attach Pyunggang(平康), Chulwon(鐵原) to the Mt. Acha (阿且山). During Japanish reign to Korea, the troop of Japan utilized this road, when the communist Army of China invaded Korea in 1951, they utilized this road also. For that reason, the present writer judge the fortress of Baegje to defend the Bidugjae barrier is the mountain fortress of Gomori, namely Gomuru castle. In connection with the judgement, the present writer will show two evidence. Recently the present writer collected the many broken pieces of the earthen ware of every kind at inside and outside of this mountain fortress, those agree with those of Mongchon's mud wall(蒙村土城) of Baegje, these agree with the broken piece of the earthen ware of the form and pattern to be picked out in the residential area of Baegje, namely in Jajagri(自作里), the town of Pocheon.