Taboo Jutsu

The Taboo Jutsu is available after your main character reach 1 RI Lv.1 (the icon will appear in the Functions menu). Its purpose is to raise some of your stats via "Learning" (obtaining material and crafting and equipping several items).

Game Help:

There are 3 important folders in the upper right corner of the main screen - Practice, Synthesize and Bag. Also Go to Land of Taboo button in the lower right corner and Inherit option in the lower left corner.

Practice

Note: Any ninja in your team can learn Taboo, its not restricted to those who are Reincarnated.

There are 5 Taboos, each of them can enhance one specific stat of your ninjas.

Taboo Endurance = HP
Taboo Elegance = Speed
Taboo Rage = Physical/Strategy Attack
Taboo Barrier = Physical Defense
Taboo Shield = Strategy Defense

Every Taboo has 7 Ranks and each Rank has increasing number of slots (from 4 to 10) which you can fill with crafted taboos. Every time you put crafted taboo in the slot, you will "learn" it, which will raise related stat by certain amount of points.
Each Rank and every kind of Taboo needs specific crafted taboos, so for example you can't put crafted Rank-5 Taboo Endurance into the Rank-2 slot for Taboo Barrier.
Once you put crafted taboo in the slot, you can't take it away and give it to anyone else.
When you "learn" whole Rank (fill all of its slots), you will also get some additional bonus related to the Taboo under which the Rank belongs.

Rank	Boost per each crafted taboo	Slots in Rank	Sum	Bonus for learning whole Rank	Total
Rank-1	+ 2,400	x 4	9,600	+ 960	10,560
Rank-2	+ 4,800	x 5	24,000	+ 2400	26,400
Rank-3	+ 7,200	x 6	43,200	+ 4320	47,520
Rank-4	+ 9,600	x 7	67,200	+ 6720	73,920
Rank-5	+ 12,000	x 8	96,000	+ 9600	105,600
Rank-6	+ 14,400	x 9	129,600	+ 12960	142,560
Rank-7	+ 16,800	x 10	168,000	+ 16800	184,800
Total					591,360

Rank	Boost per each crafted taboo	Slots in Rank	Sum	Bonus for learning whole Rank	Total
Rank-1	+ 300	x 4	1,200	+ 120	1,320
Rank-2	+ 600	x 5	3,000	+ 300	3,300
Rank-3	+ 900	x 6	5,400	+ 540	5,940
Rank-4	+ 1,200	x 7	8,400	+ 840	9,240
Rank-5	+ 1,500	x 8	12,000	+ 1200	13,200
Rank-6	+ 1,800	x 9	16,200	+ 1620	17,820
Rank-7	+ 2,100	x 10	21,000	+ 2100	23,100
Total					73,920

Rank	Boost per each crafted taboo	Slots in Rank	Sum	Bonus for learning whole Rank	Total
Rank-1	+ 300	x 4	1,200	+ 120	1,320
Rank-2	+ 600	x 5	3,000	+ 300	3,300
Rank-3	+ 900	x 6	5,400	+ 540	5,940
Rank-4	+ 1,200	x 7	8,400	+ 840	9,240
Rank-5	+ 1,500	x 8	12,000	+ 1200	13,200
Rank-6	+ 1,800	x 9	16,200	+ 1620	17,820
Rank-7	+ 2,100	x 10	21,000	+ 2100	23,100
Total					73,920

Rank	Boost per each crafted taboo	Slots in Rank	Sum	Bonus for learning whole Rank	Total
Rank-1	+ 210	x 4	840	+ 84	924
Rank-2	+ 420	x 5	2,100	+ 210	2,310
Rank-3	+ 630	x 6	3,780	+ 378	4,158
Rank-4	+ 840	x 7	5,880	+ 588	6,468
Rank-5	+ 1,050	x 8	8,400	+ 840	9,240
Rank-6	+ 1,260	x 9	11,340	+ 1134	12,474
Rank-7	+ 1,470	x 10	14,700	+ 1470	16,170
Total					51,744

Rank	Boost per each crafted taboo	Slots in Rank	Sum	Bonus for learning whole Rank	Total
Rank-1	+ 210	x 4	840	+ 84	924
Rank-2	+ 420	x 5	2,100	+ 210	2,310
Rank-3	+ 630	x 6	3,780	+ 378	4,158
Rank-4	+ 840	x 7	5,880	+ 588	6,468
Rank-5	+ 1,050	x 8	8,400	+ 840	9,240
Rank-6	+ 1,260	x 9	11,340	+ 1134	12,474
Rank-7	+ 1,470	x 10	14,700	+ 1470	16,170
Total					51,744

Synthesize

Here you can create your crafted taboos, which you can then use for learning.
As already said, each Rank and kind of Taboo needs specific crafted taboos, so before you craft something, select carefuly which Taboo type and Rank you want.
Every kind and even Rank of crafted taboo needs different material. You can obtain material in Land of Taboo.
The amount of material needed for craft is always the same, regardless the kind of Taboo or the Rank. For every crafted taboo you need 5 Occult Scrolls, 25 Horns and 8 Stones.

Rank	Output (crafted taboo)	Required material			Name prefix
Rank	Output (crafted taboo)	Occult Scroll	Horn	Stone	Name prefix
Rank-1					Rough
Rank-2					Common
Rank-3					Good
Rank-4					Fine
Rank-5					Superior
Rank-6					Epic
Rank-7					Perfect

Rank	Output (crafted taboo)	Required material			Name prefix
Rank	Output (crafted taboo)	Occult Scroll	Horn	Stone	Name prefix
Rank-1					Rough
Rank-2					Common
Rank-3					Good
Rank-4					Fine
Rank-5					Superior
Rank-6					Epic
Rank-7					Perfect

Rank	Output (crafted taboo)	Required material			Name prefix
Rank	Output (crafted taboo)	Occult Scroll	Horn	Stone	Name prefix
Rank-1					Rough
Rank-2					Common
Rank-3					Good
Rank-4					Fine
Rank-5					Superior
Rank-6					Epic
Rank-7					Perfect

Rank	Output (crafted taboo)	Required material			Name prefix
Rank	Output (crafted taboo)	Occult Scroll	Horn	Stone	Name prefix
Rank-1					Rough
Rank-2					Common
Rank-3					Good
Rank-4					Fine
Rank-5					Superior
Rank-6					Epic
Rank-7					Perfect

Rank	Output (crafted taboo)	Required material			Name prefix
Rank	Output (crafted taboo)	Occult Scroll	Horn	Stone	Name prefix
Rank-1					Rough
Rank-2					Common
Rank-3					Good
Rank-4					Fine
Rank-5					Superior
Rank-6					Epic
Rank-7					Perfect

Note: Game is bugged and it's currently showing Rank-2 Taboo Shield icon also in Rank-7 craft screen. It's unknown if the Rank-7 crafted item has normal icon or if it also looks like the Rank-2 item.

Bag

Even if there is a lot of material which differ for each Rank and Taboo type, you don't need to worry about the space.
There is a special inventory, where you can find all already crafted, but still not learned, taboos (named as Forbidden Jutsu here, but don't confuse it with anything related to Forbidden Jutsu Lab), Occult scrolls and materials (Horns and Stones) and its space is not related anyhow to the space in your standard Bag.

Land of Taboo

There are 7 different Lands in which you can obtain material needed for crafting the taboos.

Land of Taboo name	Accessible from	Rewards for winning stages
Childhood in Konoha	1 RI Lv.1	Material for Rank-1 taboos
Genin Trial	1 RI Lv.20	Material for Rank-2 taboos
Orochimaru's Attack	1 RI Lv.30	Material for Rank-3 taboos
Battle of the Valley of the End	2 RI Lv.1	Material for Rank-4 taboos
Rescue Sasuke	2 RI Lv.20	Material for Rank-5 taboos
Explore Akatsuki Secrets	2 RI Lv.30	Material for Rank-6 taboos
Five Kage Conference Scuffle	2 RI Lv.40	Material for Rank-7 taboos

Once you choose your challenge in some of the Lands, you can't change it and go to fight to another Land until the server reset (00:00 server time), so choose carefully.
There is 1 free challenge per day, so if you are strong enough, you can beat one Land per day.
Those who have active Kaguya Power can buy reset options with up to 3 daily resets, based on their Kaguya Power Level (so they can beat up to 4 Lands per day).

When you enter the challenged Land, there are 6 Stages with fights against enemy teams. Stage 3 and Stage 6 include even the named ninja (miniboss).

Childhood in Konoha — Example of the Stages from the first Land

During one challenge, you can visit each Stage only once, but you have unlimited attempts to beat it. Once you win in the Stage, you are rewarded with random amount and type of craft material (but still only in Rank related to the selected Land) and next Stage within the Land is unlocked for you.
You can select difficulty level of the fight for each Stage separately via the Switch button.

Higher difficulty gives you more material when you win selected Stage, but the fight is also much harder.
Once you clear some Stage in all 3 difficulties, you can also claim the clearance bonus reward (enough material to craft one taboo in Rank related to the selected Land). But be aware that higher difficulties are harder than even lower difficulties in higher Lands.

You can check the battle stats here.

Inherit

You can transfer some of your learned taboos from one ninja to another, pretty much like you can Exp Inherit between them. And in the same way, not all of them will be transfered, so choose wisely before you start the process.

Note: Pay high attention the game tip - Each ninja can only have one chance to transmit or inherit !