Bungo to Alchemist Wiki


There are two types of book delves (潜書, sensho).

These two are "tainted book delve". When you click on the Tainted Book or the Sealed Library icon, it brings you into the world of a tainted book where you must vanquish various types of tainted creatures in order to successfully cleanse the book.

These two are "ensouled book delve". From Equipment Books you will be able to transmigrate writers or summon their equipment including alternate outfits and memoria cards. Ensouled Books of Storytelling are the ensouled books where the writers were once transmigrated from, and by delving into them again, writers can acquire Awakening Rings.

Book Delve ss 01.png

Tainted Book Delve

Tainted book delve icon.png

Once you click on the Tainted Book (有碍書, yuugaisho) icon, you will enter this panel where you will see lots of books. This is the place where you will spend most of your time in the game beside clearing the ongoing Events.

Book Delve ss 02.png

These books are sorted into the i-ro-ha [いろは] sequence, which is a traditional ordering of the Japanese syllabary, a system similar to 'ABC'. The wiki will be using i-ro-ha [いろは] as reference to the various combat stages within a series of books.

The first series is the i-series [い], with the first book named as i-1 [い-1]. You may select different books to cleanse by clicking on the i-ro-ha [いろは] tabs on the left, clicking on a book's spine, and then by choosing a team, you may delve from the Delve (潜書) button on bottom right corner.

A Fire element team ready for delve

The Four Elements

Each book has its unique taints and recommended element (displayed on the top-right corner of the book with an elemental sign) you should consider when forming teams in Formation and choosing a team for the delve. You can obtain more information in the Tainted Books, where a full list of the books may be found.

Once you enter a tainted book, your party will meet with different types of tainted monsters. You can obtain more information of them by accessing the Taint Types section.

The battles consist of three waves, and usually the last book (fourth book) of each shelf have a bigger taint in last wave of the delve, which is considered the "boss" taint. To bring down the taints, your writers will execute different kind of attacks depending on their status. Some of these status effects usually trigger when the "corrosion value" (also known as HP) of a writer drops too low or they've been attacked on a long run to fill their Epiphany Gauge. More info of the game's combat mechanics can be found here.

Book purification complete

Upon complete purifying of the tainted book, you will be rewarded the writer of the book (do note that this is a reward for clearing the book for the first time only). List of all writers can be found here.


Auto-Delve that has reached its resource limit

Auto-Delve (自動潜書) becomes available once you have cleared the first book of the i-shelf (i-1). Writers will go patroll in the books automatically, and through time gather items. The further you advance in the shelves and purify books, the bigger amount and rarer items you may acquire through the auto-delve. The items you can get are Alchemy Thread (Thread icon.png), different kind of Souls (Words Soul (Small) icon.pngWords Soul (Medium) icon.pngWords Soul (Large) icon.png) and Soul Gears (Soul Gear icon.png).

Memory Gears (Memory Gear icon.png) and different kind of Splendor (Words Splendor icon.png) may be acquired from Auto-Delve upon clearing Tainted Book RU-1 "Madam Pearl" (真珠夫人).

Medicine (Unusual Medicine (Gun) icon.pngUnusual Secret Medicine (Gun) icon.png) and Unusual Crystal (Unusual Crystal icon.png) may be acquired once clearing Tainted Book WO-1 "Gon the Little Fox" (ごん狐).

You may claim the auto-delve rewards by pressing the yellow button Receive Report (報告を受ける) on the right side of the screen. The longer you wait and let your writers patrol, the more items you get and likely gain some rare items.

Please do note that auto-delve hits limit after 24 hours since the last claimed report!

You must claim the auto-delve rewards at least every 24 hours or few times a day for efficient resource gathering as you can't gain more than items worth of 24 hours at a time. If your auto-delve has hit the resource limit, the golden bookmark will have text Patrolling Complete (巡回完了) and there will appear a green banner Resource Limit Met (素材上限到達) above the receive report button.

Double amount of resources from the Auto-Delve can be gained with Special Duty Aid Pass for a duration of 30 days. When said pass is in effect, a red banner Double Rewards (報酬2倍) will be displayed on top of the receive report button. In Main Library there will also be a blue button Special aid active (特別支援中).

Sealed Library

Sealed Library icon.png

Sealed Library (封蔵書, fuuzousho) is another section of Tainted Book Delve with similar game mechanism, introduced during the Purify "Alice's Adventures in Wonderland" event as part of the Foreign Secret Records storyline, which acts as a part of the game's Main Story. The Sealed Library can be accessed once you have reached player level 3.

Once you click on the "Sealed Library" icon, you will enter this panel.

Wk book delve 09.png

Books are sorted into shelves following the Latin alphabet and divided into chapters, which consist of multiple paragraphs for cleansing. The first series is the A-series, with the first chapter named as A-1, and its first paragraph being A-1-1.

Wk book delve 10.png

Most of the Sealed Library's mechanism is the same as that of the Tainted Books, with the introduction of raid bosses. During the first runs of A-3-5 and A-4-5, players will encounter bosses with huge amount of HP and be expected to defeat them by draining their HP through multiple delving attempts.


The writer Lewis Carroll is permanently available as a reward upon clearing the book Alice's Adventures in Wonderland 3.

A full list of all available Sealed Books can be found here.

Equipment Book Delve

Equipment book delve icon.png

In the Equipment Books (有装書, yuusousho), the spiritual successor of Ensouled Book Delve, you are given a chance to transmigrate writers and summon their equipment including outfits and Memoria Cards.

  1. Click on the open slot to open up the writer's list. This is where you can select a specific writer to delve into the book. Your library assistant will not be included in this list, so if you want to use them to delve into equipment books, you must change your assistant in the office.
  2. Choose your selected writer by clicking on his tab.

Overview of Equipment Books UI

Once your writer is selected, you will see the amount of Equipment Books Equipment Book icon.png and Governors (調速機) Governor icon.png you have. Once you click the Confirm button, the delving will immediately begin. For delves without the use of governors, a timer will appear. The higher timer, the more likely your result will be a rare writer or some equipment (outfit or memoria card).

Equipment books ss 02.png

If you change your mind and want to obtain your writer or equipment immediately, click on the governor icon to use a governor, which will instantly finish the delve.

See more info of Equipment Books and the timers here.

Ensouled Books of Storytelling

Ensouled Book of Storytelling delve icon.png

Ensouled Books of Storytelling (紡の有魂書, tsumugi no yuukonsho), is another gameplay feature inspired by the late Ensouled Book Delve feature.

The writers are incomplete beings upon transmigration to the Imperial Library, thus through fighting and by meeting some old friends as well as new ones, they have gathered experience and old memories from their previous lives. By delving into the very Ensouled Books where the writers were transmigrated from, they will find who they really are and what they are capable of, leading them to awaken new power by acquiring mysterious items called Awakening Rings (覚醒の指環, kakusei no yubiwa). See Awakening Story Prologue for further info of what the rings are about.

Please do note that the Awakening Rings are different from regular Rings, that change the writers' weapon type.

Ensouled Books of Storytelling main page, where Dazai Osamu has been highlighted

Select a writer of your choice who has an Awakening Ring available for acquisition (from the list on the right), and press the yellow button Delve (潜書). In case there is a finished delve, the yellow button will display text Finish (完了). If the writer you want to choose for delving doesn't show up on the list, make sure he isn't already delving to another book, he isn't your assistant and that he actually has an Awakening Ring implemented.

Ensouled Books of Storytelling 02.png

After pressing the delve button, you will be shown info of the delve cost, and what is your exploration success rate; at what rate you might acquire Recollections (回想). The higher level the writer is, the higher chances he has to get a recollection (for a level 60 writer the maximum chance is 30%). Confirm the delve by pressing the yellow button Confirm (決定) and you will see a timer, which will result in one of the following things:

Timer Result
00:10:00 5x Small Souls (any color)
00:20:00 2x Medium Souls (any color)
01:00:00 Recollection
Duplicate of delving writer's regular outfit
200x Ink
1x Large Soul (any color)
1x Unusual Medicine (any color)
1x Unusual Secret Medicine (any color)
1x Unusual Crystal
1x Soul Gear
1x Memory Gear

If you didn't use Governor (調速機) before delve and wish to skip the waiting time, press the yellow button Use Governor (調速機を使用). You will be asked to confirm this action with yellow "Yes" (はい) or silver "No" (いいえ). In case you let the timer run out on its own, the yellow delve button will display text Finish (完了). Press it to collect the delve result.

Ten (10) recollections must be gathered to unlock a special delve, which will reward the Awakening Ring.

Dazai Osamu prepared for the special delve

Once you have gathered 10 recollections, on top of the screen in delve confirmation, make sure that the slider for Awakening Story - Final Chapter (覚醒ノ物語 終章) is "On" (潜書する) and press confirm. You will be taken to a screen where you see a team consisting only of the writer whose Awakening Story you are trying to complete. The team or the writer's outfit can't be changed. Press the red round button Delve (潜書) on the bottom right of the screen to start the delve.

Clear the delve to acquire the writer's Awakening Ring. In case you have troubles beating the boss, try leveling up the regular outfit and make sure the writer has been strengthened through Blossoming. There is one extra recollection before the actual delve and after defeating the boss, resulting in overall 12 recollections for each writer's Awakening Stories.

See list of all available Awakening Rings here.

A list of all Awakening Stories can be found here, or from each writers' recollection pages.

Questions regarding delving

  • Why am I unable to delve into a Tainted Book?

One or multiple writers in your delving team are currently delving into Equipment Books or Ensouled Books of Storytelling. Finish their delve and try delving into Tainted Books again.

  • Why am I unable to choose a writer to delve into Equipment Books / Ensouled Books of Storytelling?

Is the writer you are trying to use currently as your assistant? Or perhaps already delving into the other option? Writers who are assistant can't delve into Equipment Books / Ensouled Books of Storytelling, so change your assistant before attempting to delve. In case the writer is delving to other book, finish the delve to release him.

  • Where can I get more Equipment Books / Ensouled Books?

Equipment Books are rare items given through daily and weekly Research Missions, as well as common Event Rewards or at times, given through Campaigns. Ensouled Books are about the same, being rather rare items given through multiple ways like the Equipment Books.