Gojaku Peak / Jakobe Pass / 1976 / 18:00:03
Chapter 1 tells the story of a girl with a tragic fate, hinting at the curse that binds Hanuda Village. Set in 1976, it illustrates the ritual that came before "the ritual that revived Datatsushi" in the game (27 years ago). By the time it begins the mother of the protagonist, Namiko Yoshikawa, has already gone missing, and Namiko herself has witnessed a strange light that "appears to float down the contours of the mountain", points that reinforce how Hanuda Village has long been viewed as a place where strange phenomena such as spiriting aways and mysterious bodies of light occur.
Searching for her missing mother, Namiko heads for the mountains containing Gojaku Peak. She becomes worried and decides to return to the village, but sees "something" strange that resembles a wild dog, and falls down a hole as she flees from it. Due to sipping the "red water" inside this hole, its effects gradually begin to turn her into a half-shibito. As can be confirmed by viewing the in-game archive items, Namiko went missing on the fifth of July, 1976. About a month later the "secret ritual" failed, and the village was sucked into the Other World (which appeared on the surface as the village being covered and destroyed by a landslide), but it is unclear at which point Namiko begins to suffer from the effects of the water. You can interpret it as appearing due to the ritual failing for some reason and the village becoming trapped in the Other World, or perhaps it had appeared in the area around the hole Namiko falls into preceeding the ritual (since Hanuda Village sits in the unstable rift between the real world and the Netherworld).
Namiko, slowing turning into a half-shibito at the bottom of the hole, is granted the ability to see "visions" by the water's effects. She witnesses "a girl wearing with night-black hair and white skin, wearing a white kimono", who is the very same Previous Miyako from Chapter 2. And the solemn procession carrying an empty coffin... There is a strong possibility that this was the Kajiros' way of covering up the fate of Previous Miyako after her escape, but saying she vanished (refer to chapters 2 and 4), but there is also the possibility that it belongs to Namiko, having been believed to have died without her body ever being found.
As she sees these scenes, which she cannot distinguish between dreams and reality, Namiko slowly changes at the bottom of the hole. Finally she turns into a "dog shibito" and escapes from the hole and, relying on her only remaining thought admidst her muddy consciousness - "I have to go home" - she makes for her house. And there, she encounters a "girl with a red backpack" on the mountain path... This tells of her tragic, sad fate. As I'm sure you are already aware, long ago it was Namiko herself whom she saw on the mountain path, the "wild dog" that was the very thing from which she was trying to flee... Seeing the red backpack and the stone statue she saw all that time ago, dog shibito Namiko turns and scampers away on all fours. Perhaps at this point she realised she couldn't go back...
The paradox of the girl surprised by her own future monstrous form and a story about a loop shut in time - these are very interesting as insights into Ouroboros, an endless cycle without distinction between beginning and end, and the world in which Siren is set.
-Girl with a red backpack
The girl who goes up the mountain path to Gojaku Peak is Namiko Yoshikawa. As is written in Chapter 1's epilogue, after turning into a dog shibito Namiko appears in the school library, but at this point she is "an incomplete dog shibito that has been unable to go to the sea" (via Ms. Sato). Due to this, in the real world, which operates on different principles to the Other World, "her joints twist the other way around to those of normal dog shibito" (Sato).
-Girl in black kimono
This is Previous Miyako, who appears in Chapter 2. Since she lived in the Kajiro house with no human contact, Namiko doesn't see her all that clearly.
The title of the borrowed book is "Folk Tales of Hanuda Village". A total of six names are written here, the last one naturally being Namiko Yoshikawa's. Since this is obtained in eastern shaft 3 at Gojaku Peak, the possibility that this is the shaft Namiko fell into is high. Incidentally, the name of the fifth borrower can be faintly made out to read "Hisako Yao".