I believe it's the jewel shards that allow them passage, but other then that I've always believed it was the enchanted beaded necklace he wears that allowed Inuyasha to pass through the well to Kagome's time. It's connetted to Kikyo's soul, because she was the one who enchanted it to be used on him originally, which links him to Kagome who currently holds the spell, and that connection allows him to follow after her.
An easy example of this is in episide 3 "Down the Rabbits Hole and Back Again" Inuyasha, without any jewel shards on his possession lept through the well after Kagome so he could drag her back to his time. To me that said enough.
About the demons being able to pass through it I believe this only happened twice in the story. The first time was when Kagome was caught by the Mistress Centipede and got dragged to the Feudal Era in episode 1, but we learned later on (in a filler episode of course) that the centipede pased through the well because of her bones that were thrown in the well after she had been slane. Her soul apparently went with them, some how sensed the Shikon Jewel in another time zone beyond it and struck out and nabbed Kagome. The second time a demon passed through, wasn't actually a real passage either, but was when Yura of the Hair was persuing Inuyasha and a strand of her hair was clong to his kimono when he passed through unwittingly bringing her hair along with him. I don't think her hair would have been able to pass through other wise. Although she did have a jewel shared in her possession at the time as well. The one she stole from Kagome in the previous episode. *oopse* edit ^^
well all i know is that kagome can travel through the bone eaters well because of:
1)she is the reincarnation of kikyo.
2)she carries shikon jewel shards
well inuyasha? not sure. but here is my theory:
1)i remember one time (not the ep like 18. the one where inuyasha takes kagome's jewel shard after first meeting naraku) i saw him pulling the little jar of shards out of his kimono. but kagome was next to him wearing her giant shard with her.
as for other demons? not sure. i guess that how rumiko takahashi wanted it. maybe she thought that would go with the situation and story line. who knows
posted over a year ago
maybe because inuyasha has been sealed to the tree by kiyo's sacred arrow so he's been touched by the jewel or something like that...
About above comment, I fail to see the relevance in this, Kikyo was the Jewel's guardian at the time but she wasn't a part of it, like Midoriko is. So I disagree. The Jewel didn't get attached to Kikyo/Kagome until after Kikyo's death and it was burned with her remains, and having been reborn (or just returned) with Kagome...:/
The Shikon no tama can open the passage. When they lose the fragments of the shikon jewel they can no longer pass trough. In some cases they can pass without the jewel but that is because they have been "contaminated" by the quantic state of the other time period.
