PDP Guide Part 5: Reaching the Bamboo Forest

Part 4 can be found here.

The last section covered the Forest of Magic, and now this section will be covering getting to and through the Bamboo Forest of the Lost and Eientei.
To start with, make your way back to the Human Village and to the Hieda Household. There, you'll be able to speak with Keine about Eientei.
After that, head down past the Dragon Statue and keep going down. There will be a man standing near the entrance to a new area. He'll let you by now that you have a Bicycle and have spoken to Akyuu. Head down past him. Or first, if you like, you can head to the right through town until you reach a shop with a big blue curtain-thing. This is the Tailor, where you can change your Puppets' costumes for 3000 Yen each. This is a neat little feature that you can use if you'd like. It has no effect except for aesthetic purposes, so feel free to pick the costumes that you like best. Okay, now go where the guy just let you through, okay?

In this new area, you can find Kotohime, Yatsuhahi, Benben, Nue and Kyouko.
You may also want to get your highest up to level 27 or so if you aren't already. If you happen to hit level 30, you should immediately Edit your Puppet and do Style Change. This change is permanent, but any Style will have higher stats and benefits than a normal, unstyled Puppet. As far as I know, there is no purpose to keeping your Puppet unstyled, so pick whichever Style seems useful to you.

If you go through the large grass patch you can fight a pink Youkai (Tsutsuji) who uses a level 17 Kokoro.
After that, head down the nearby stairs until you see a little shrine-thing and a Yin Yang Orb containing a Rice Dumpling.

Now, here, you actually have a choice! Heading down will take you to the Bamboo Forest of the Lost, while heading to the right will bring you to Myouren Temple. There isn't really anything to do at the Temple yet, aside from defeat trainers, and catch Puppets. It's good exp though. You will come back here later anyway, but you won't benefit from the trainers as much then. It's optional right now, although beneficial, for certain!

The guide to Myouren Temple can be found here.

If instead (or perhaps after), you decide to go to Eientei, head directly down from the little shrine.  You will see a girl in pink and a house (empty at this time).  If you head to the right from the house you can fight a beast Youkai (Fuyou) who uses a level 15 Chen and a level 15 Kagerou.
To the left of the house, you'll find some grass. Go through it to reach a Yin Yang Orb containing a Clarity Charm. Hop the ledge and fight the Puppeteer (Erika) who uses a level 17 Kotohime. Then continue right past her and then go down the path.

Keep heading down the linear path to the cloaked Youkai (Riko) who uses two level 17 Kurumis.
There's some grass a bit past her, which contains Kurumi, Elly, Mystia, Mamizou, and Seija (rare).
Be warned that Seija will almost always run away from battle. In my experience, she tends to do this on the second turn, so if your first Seal misses or your Puppet is slower than her, don't expect to catch her. It's possible, of course, but it seems like that's when she runs.

Just below the grass is a Novice Puppeteer (Hinako) who will fight you if you talk to her. She uses two level 17 Kotohimes. Past her, you'll be challenged by a Farmer (Kengo) with a level 19 Yuuka. Past him a ways is a brown Fairy (Hibari) who will fight you with two level 17 Rumias.
Continuing from there you will see a Yin Yang Orb and a pier, along with the path winding to the right. The Yin Yang Orb contains a Quartz Hairpin, which will boost the power of Earth-type skills when given to a Puppet to be held. On the pier is a Rascal (Shouta) who will fight you with a level 17 Seija.

Continue following the path to the right. You will see a Yin Yang Orb below you that you can't quite reach yet. Keep going forward until there is a break in the trees below you and go through the grass to get it. It contains a Contract Thread, which is a better quality thread than simple Seal Thread (as in, it is less likely to miss).
Continue across the bridge. Below you, you will see a grassy area, if you go through there a ways you will come across a Yin Yang Orb containing a Burn Charm (which might be useful coming up against Mokou). Jump off the nearby ledge and go left just a bit to fight Kagerou. She uses a level 16 Wakasagi, level 17 Sekibanki, and a level 18 Kagerou.

Continuing right and up, you'll be challenged by a Maid (Kazuha) who uses two level 17 Youmus. Ahead of her are two people standing next to each other, but neither will fight you. Go up from them and you'll find an Inn. The Yin Yang Orb beside it contains a Rice Dumpling. Inside the Inn you will find a likely much-needed Healer and shopkeeper who sells Thread (the man in blue near the desk). You can buy Contract Thread here, which is a nice change! He also sells Skill Cards for some support-based skills.

Outside of the building, if you follow the path to the right, you will be at the Bamboo Forest of the Lost, but let's explore the left first, shall we? It's extra exp, which is important for what is to come.

First off, you'll see a bridge and two Youkai standing near it. They will both fight you if you talk to them. The pink one on the right (Asami) has a level 19 Mamizou, and the purple one of the left (Natsume) has a level 19 Nue.
Go across the bridge and when you get to a space in the trees allowing you to go down, do so (there is nothing straight ahead, except a ledge to get you back to the Human Village faster).
Down there is a beast Youkai (Sayaka) with a level 17 Chen and a level 17 Nazrin. Continue past her through the grass and you'll run across two fairies; members of the Liberation Front. The one with brown hair (Fleur) uses a level 17 Nazrin and a level 17 Kyouko. The one with purple hair (Wenny) has a level 17 Luna and a level 17 Daiyousei. Up past them is a Yin Yang Orb containing Skill Card 20. This contains Clearing Mist, which increases in power the higher the Cost of the Puppet you're fighting compared to your own. So basically, the more rare the Puppet you're fighting is, the more damage it will do (unless your own Puppet is equally rare). You can check your Puppet Book or the wiki for information about what Cost every Puppet is.
While you're here, you may want to level up in the grass a bit. I recommend having all Puppets to high 20s, if not 30s, and your Starter should really be 35 at least, if not higher. There is a better leveling place coming up soon, but I would advise leveling a bit here too just to give yourself a little buffer for the next couple fights before then. I guess just be sure your starter is at 35 and you have at least one other level 30, and you should be fine to continue.

Now, head on back to the Inn where you can heal, stock up on supplies, and head on to the right and into the Bamboo Forest of the Lost!

Thank you to an Anonymous commenter for the information that Nue can be caught on the route between Myouren Temple and Eientei.

Link to Part 6 here!