im curious as well
reading the comments in the jpwiki, there r some speculations
some said they unlocked it after clearing the beginning trial
one said he realised it's unlocked after he cleared mysterious dimension, but not beginning trial
some said need to kill shopkeeper mamizou & rinnosuke (not the boss) in beginning trial
theres also speculation tat ur total $ gained is also a factor

honestly, idk .-. hard to figure out these stuff

- It's definitely not Mysterious Dimension without Beginning Trial since I have finished the former and not yet the latter
- Beginning Trial might be true (I will tackle this dungeon next, afterwards we'll see)
-The shopkeeper ones might be correct as well. I think I will test whether it is unlocked already after beating the shopkeepers or really only after making it through all of Beginning Trial by using a backup save
-I've tested the money one by giving myself 999999999 on hand and 999999999 in offering box with CE but nothing happened after reloading the shrine. Might have to do with total "earned" money (I only increased the currently held money) but I do not know if that's even being tracked (or if it makes a difference)

I also suspected it had something to do with stealing from a shop since the item sounds like it could be a Mamizou related weapon (it also requires Tanuki Ornament) but alas, no results (except for losing my bonus 10% for Crime & Punishment T_T).

from the in-game description of the weapon (found and translated from jpwiki):
"An abacus said to be once favored by a merchant who mastered the trades. The soul of a merchant dwells within. It's said to be able to do all calculations perfectly and never makes any mistakes."

don think tat's gonna help much tho .-.
gonna be difficult to find a shopkeeper rinnosuke tho since he's rarer than mamizou...

Wait does he spawn in regular shops as well when you steal?

there's a very small chance to encounter him as the shopkeeper instead of the usual mamizou family in certain dungeons, rinnosuke replacing mamizou, and rinnosuke robos replacing the kid tanukis
most of them are basically skin diving dungeons, with exception to just Golden House

the dungeons are:
Old Well at the Hakurei Shrine
Old Well in the Mausoleum
Hakurei's Trial ~Challenge from the Moon~
The Wild Fire
Fairy Well
Old Well of Moriya Shrine
Time's Altered Space
Mysterious Dimension
The Beginning Trial
Golden House
Blood is Life
Noir Vengence

there are also 5 dungeons tat he might appear, but it's not confirmed yet:
Junk Garden
Cork Screw
Luna Labyrinth
Moon Junk Garden
Platinum House

I saw Rinnosuke in C Re:mains

Well, i found out i have this recipe already. But i have no idea where it taken from, as i've completed every (i guess) trial, Beginning trial and Myst.Dimension inclusive. BUT Dimension gives you an Aggressive Gap recipe, so i guess this is not you're looking for.

I have unlocked it. You have to clear The Beginning Trial for it. I think the unlock condition is either beating the dungeon or defeating Rinnosuke?, the boss on F99 (if you've come that far, I don't think you will die before using the magic circle though). After all, you even get a cutscene (with a major plot twist) after beating the dungeon and he gets his own entry in the bestiary.

I'm pretty sure you don't unlock it from just clearing the beginning trial by itself. I cleared that months ago and didn't have the merchant's spirit recipe today. I cleared mysterious dimension and also killed mamizou twice in Bullet Report on Yokai Mountain(was finally unlocking Wild Fire). Sadly I didn't think to check in-between MD and Mamizou, but I'm fairly certain killing mamizou at some point is at least 1 requirement.

I've finally finished the "Beginning Trial" dungeon (it was a pain on 98 floor). it took me 10 retries with Reimu. and the last boss was stupidly easy. One question though. In some videos there's players that had Rinnosuke/Buyking's katana (the Kusanagi i think). It is possible to craft that katana now that i've unlocked the final recipes ?

Originally posted by AkaYoukai:

I've finally finished the "Beginning Trial" dungeon (it was a pain on 98 floor). it took me 10 retries with Reimu. and the last boss was stupidly easy. One question though. In some videos there's players that had Rinnosuke/Buyking's katana (the Kusanagi i think). It is possible to craft that katana now that i've unlocked the final recipes ?

Yes. The recipe for Kusanagi-no-Tsurugi is unlocked after clearing Beginning Trial, it's near the absolute bottom of the weapons page and is made with: Sokanto Sword, Set of Six Coins, Old 10,000 Yen(10 Charges), and Money Gap(9 slots).

I've craft that and... it wasn't something i did expected. The first thing unexpected is that the weapon is a two handed sword as i thought it was an one handed weapon. I mean Rinnosuke/Buyking
were able to hold it with only one hand. The second thing unexpected for me (and probably expected for any of you) is that the weapon consume ALOT of money, especially in it final form. (I don't really dare to meld it with my Sky Fox Infinite Sword (which i meld it with the Yorihime's sword, and many Lord of Hakureis) afraid i would no longer be able to use my best armor until now). Sure i would remove the money consuming seal but i'm not very confident to meld it with my best weapon. Surely i would use many Lord of Hakureis to make the weapon far powerful enough to equal the Sky Fox Infinite Sword's current Atk, Lvl. Other then that i have not much left except trying completing my Bestiary (with Rinnosuke and his bot), and get 2 more achivements as i already defeated the Innocent Heart. And the Mysterious Dimension was a real living hell (No way in million years i'll go back there)

Even through i've unlocked the final recipes it seems that i cannot craft other weapons below the DLC weapon (except the food weapon), or the other pellow just after Buyking's body pellow. Do i need to clear the Beginning Trial again or should i do the delivery thing ? (Which i really hope not)

No definitely not. I've never even touched that dungeon but still had (I think) virtually every weapon entry. I'm not sure though since I havent touched this game for like 2 whole years now.

Originally posted by AkaYoukai:

Even through i've unlocked the final recipes it seems that i cannot craft other weapons below the DLC weapon (except the food weapon), or the other pellow just after Buyking's body pellow. Do i need to clear the Beginning Trial again or should i do the delivery thing ? (Which i really hope not)

There's a guide in the guide section called Items, Recipes, Seals, Bestiary List. Go read that to find your answer.