These scrolls are necessary to the Ninja job. Also, if you are sure you will never level Ninja, then these are good to sell.
To acquire these scrolls, you will first need to get Norg/Tenshodo fame. Most of the Ninja scroll quests and Trial by Water summoner quest can be obtained with Level 4 fame.
The easiest way to raise this fame is:
1. Complete the Shady Business quest in Port Bastok.
A. Enter Warehouse 2 (marked on your map) and go downstairs.
B. Speak with Talib; he is located behind the stairs and dressed in red. You will get a cut scene.
C. Trade 1 zinc ore to him, for which he gives you a key item.
D. Go to the residential area of Bastok Mines and walk down the slope. Enter the door at I-7 and talk to Pavvke. He asks you to talk to a girl, but you don't have to in order to finish the quest.
E. You can now turn in 4 zinc ores to Talib for 350 and this is repeatable.
Zinc ore can be obtained from killing worms or you can purchase it at the Goldsmith shop, but it goes quickly. You can also mine it in Zeruhn mines. Also avialable on AH, but not cheap.
**You will need approximately 120 zinc ores**
2A. Complete The Brugaire Consortium quest in Sandoria Port:
1. Talk to Fontoumant in Cargo Room B at H-9 in Sandoria Port. He will ask you to make some deliveries for him.
2. Talk to Regine in the Magic Shop at J-8 and trade the delivery item.
3. Talk to Apstaule who is standing near the Auction House and trade the delivery item.
4. Talk to Thierride at the Rusty Anchor Pub at G-7 and trade the delivery item.
5. Return to Fontoumant at H-9 and talk to him to receive your reward of a Luauan shield and completion of quest. This is a prerequisite for the following quest.
2B. Complete the quest A Job for the Consortium in Sandoria Port. This is kind of risky, because if you fail, you'll have your airship pass revoked for a while.
A. Prerequisites for this quest are Rank 5 or having airship pass and be a member of the Tenshodo guild.
To become a Tenshodo member:
1. Enter Neptune's Spire in Lower Jeuno at J-7. Go to 2nd door on left and enter the room. Speak with the Taru named Sutarara.
He talks about the Tenshodo being right under your nose.
2. Speak with Ghebi Damomohe behind the counter. Scroll down to and choose the third BLANK line. Ghebi will say you need either a Tenshodo invite or an application form.
a. The Tenshodo invite can be bought at the auction house. It is found under Others/Miscellaneous - it costs about 20K as of this writing.
However, you can resell it as soon as you get your Tenshodo membership.
b. Or, if you don't want to spend the gil, you can go to Port Bastok and speak with Jabbar in Warehouses #2 (located across from Airship) at F-6. He will give you an application.
B. Talk to Portaure in Cargo Room B. He gives you a key item.
C. You must take the airship from Sandoria to Jeuno, no walking, warping, or choco riding allowed.
D. When you arrive in Jeuno, you'll pass through customs. There is a chance you'll be caught and arrested, your key item confiscated, and airship pass revoked for a short period of time (until midnight Japanest time).
E. If you make it through Customs, you'll see "You have cleared customs."
F. Go to the Tenshodo Headquarters in Lower Jeuno and talk to Yin Pocanahu, who thanks you and tells you to return to Sandoria Port and talk to Portaure again.
G. You receive 1,000 gil and more fame.
H. This quest is repeatable.
3. Complete Mihgo's Amigo quest in Windurst Woods.
A. Go to J-3 in Windurst Woods.
B. Talk to Nanaa Mihgo's buddies and then to Nanaa herself.
c. She asks for a gift, which is 4 Yagudo necklaces.
D. Yagudo necklaces drop from Yagudos in Sarutabaruta and Giddeus. You can also find them on the AH under other/beastmade
E. You will get 200 gil for every 4 you turn in.
F. This quest is repeatable.
**It is speculated that about 200 necklaces will give you enough fame for the scrolls.**
To check your Tenshodo fame level:
1. Check the price of rice balls sold by Ghebi Damomohe in the Tenshodo Headquarters in Lower Jeuno J-7 in Neptune's Spire Inn. Check guide below. The minimum price rice balls will drop to is 144.
*****Please note that the price of rice ball method is no longer as accurate as it used to be. In one of this year's past updates, Square changed it so that the price of an item fluctuates by how many were bought in a previous game day, whereas it used to only be based on your fame in that town/region. So your only true fame indicator is from talkling with Vaultimand in Norg.****
2. Visit Vaultimand in Norg at H-8.
Level 1
Who the hell are you? [Name]? Never heard of ya. How am I supposed to remember the name of one puny ant when there's millions of ya swarmin' around?
Rice Ball Price: 186-172
Level 2
[Name]? I mighta hearda somebody that went by that name, but I meets a lot of people in me line of work. Don't look so upset there, matey. It takes a lot t'get people t'remember ya. It all starts with trust!
Rice Ball Price: 169-168
Level 3
Wait a minute, I remeber you...Mich...no...[Name], right? Ya see, do a little work, and people start recognizin' ya. Keep up tha good work!
Rice Ball Price: 164-163
Level 4
Well if it isn' [Name]. Hear yer name lots 'round these parts lately. Why, I remembers when you was nothin' but a measly insect. Thanks t'me advice, you're doin' quite well here in Norg.
Rice Ball Price: 160-156
Level 5
Oh, [Name]. I was just talkin' to me mateys about ya the other day. Nothin' bad, of course. They had all heard about yer deeds fer Norg. Some are even startin' t'think that maybe all you adventurers ain't so bad after all.
Rice Ball Price: 155-150
Level 6
[Name]! There's hardly a soul in Norg that doesn't know yer bloody name. Oh, sorry 'bout that. Me mum never did teach me no manners. I'll watch me damn mouth...I mean, I'll watch me mouth from now on.
Rice Ball Price: 148-144
Level 7
[Name]...Mister/Miss [Name]. You've become quite the household name 'round Norg. All me mateys keep askin' me if I can introduce them to ya. You've made quite a reputation for yerself! Lookin' at ya gets me thinkin' like I should leave tha life on the open sea, and become an adventurer!
Level 8
** I have hear of your showing activity again!
Level 9
Lord/Lady [Name]! Next t'our leader, Gilgamesh, yer the most famous person in all'a Norg! Some me mateys are even callin' ya a hero! May the light of the Dawn Goddess shine down upon ya in all yer journeys 'round Vana'diel!
ACQUIRING THE SCROLLS
Okay, you now have the required fame, so head to Norg.
You will need:
1 silver beastcoin
A minimum of 4-6 silent oils, although having more is always safer. Be sure you are in a safe spot when your sneak wears so you can recast it without aggro.
The Walkthrough for Tonko:Ichi Follow the map below.
1. Talk to Keal at H-8 to get It's Not Your Vault quest. The reward is Tonko:ichi.
2. Visit the Nomad Moogle at G-7 and change to a level 1 job. The reason for doing this is if you die during this quest, you will not lose any xp.
3. Set your home point at H-9, so that if you die, you'll return here and can start over.
4. Exit Norg (A).
5. Use your silent oil. Follow the tunnel and go through the cracked wall/door marked B at H-6.
6. After passing through the B door, turn right and follow right hand wall to door marked C at C/8; B/8.
7. Pass through C door and continue until you reach door marked D at C-6.
8. Pass through D door. You're now in a room which has a wooden floor.
9. Examine the iron box at C-5/6 (E) to receive a key item.
10. Find something to kill you and you'll return to Norg upon your death.
11. Change back to a higher level job and talk to Keal (H-8) again and he'll reward you with the Tonko:ichi scroll.

The Walkthrough for Utsusme:Ichi Follow the map above until step 8, then switch to the map below.
1. Talk to Laisren at H-7. He is located behind the 2 vendors. He'll give you The Sahagin's Stash quest. The reward is Utsusme:Ichi.
2. Exit Norg (A).
3. Use your silent oil. Follow the tunnel and go through the cracked wall/door marked B at H-6.
4. Turn left and proceed to J-5, where you will turn right.
5. Once you come to K-7, just hug the left wall. At about K-8 (F), you will go down a one-way set of stairs. Continue following the left wall until you reach L-13.
6. At L-13, start following the right hand wall until you reach the Silver door at N-14 (G). It is located at the back of a cavern between 2 waterfalls.
7. You will need to examine the door several times. Note how the description changes each time. When it says you see silver shavings around the hole in the door, trade your silver beastcoin to the door (your silver beastcoin will remain in your inventory). Pass through.
8. At this point, you will now follow the below map.
9. You'll be following the tunnel, but do not get too near the edges as they are one-way drops. Follow the tunnel until you come to a cliff at H-8 (H). Drop off heading NE.
10. Continue heading North until you come to the door marked I at H-4. Pass through.
11. Examine the chest at H-3 (J). You will receive a cutscene.
12. Find something to kill you and you'll return to Norg upon your death.
13. Change back to a higher level job and talk to Laisren (H-7) again and he'll reward you with the Utsusme:Ichi scroll.

I hope this is helpful.
**Edited on 12/28 to add information about becoming a Tenshodo member and the prerequisite quest The Brugaire's Consortium.**
***Edited on 1/4 to add information about rice balls no longer being a true indicator of fame.***
****Edited on 1/8 to tell you to change back to a higher level job due to SE putting a minimum level on these quests.****