STEINS;GATE RE:BOOT True Ending Guide – All 6 Flags
Collect all six Kurisu email flags in Chapters 4, 5, 7, 8, 9, and 10 to unlock the STEINS;GATE RE:BOOT true ending. Exact reply paths included.
To unlock the True Ending in STEINS;GATE RE:BOOT, collect all six True Ending Flags by correctly replying to Kurisu’s emails in Chapters 4, 5, 7, 8, 9, and 10.
- 0 flags → Mayuri ending (Stardust Sky)
- 1–5 flags → Kurisu ending (Paradox Meltdown)
- All 6 flags → True ending (Open The Steins Gate)
These replies are not the Chapter 4 cup-noodle achievement chain. Save before Flag 6.
Spoiler-free instructions
Load Chapter 4 (chapter quick save is fine). Follow the six blocks below. Read the follow-up mail that awards each flag — receiving it is the flag, not just sending the last reply.
Flag recovery matrix
Use this table when you are repairing a failed run and need to know where a flag can be lost:
| Flag | Chapter | Start from | Required path | Confirmation / common mistake | ||
|---|---|---|---|---|---|---|
| 1 | 4 | Did you write it? | Scientist → Bad scientist → Dad joke → Outsider → Disgrace → Why am I still here? | Read Being here. Do not take the separate Report → Cup noodles achievement branch. | ||
| 2 | 5 | Plans | Traveling expenses | Keep reading the follow-up chain through ( ´ · ω · | I don’t have a key → Security → Reality | Read the final Reality. The Frog / Home branches are collectible routes, not the flag. |
| 4 | 8 | Explain yourself! | Use the only reply | Read From an unpopular girl. | ||
| 5 | 9 | Contact me, idiot! | Worried | Read Re: Re: Contact me, idiot!. | ||
| 6 | 10 | Where are you now? | Reply Where you are | Save first: ignoring this mail gives the Kurisu ending instead, which is useful for completion but not the True ending. |
If Chapter 10 gives Mayuri, you have zero flags and should restart from Chapter 4. If it gives Kurisu after you reply to Flag 6, one of Flags 1–5 was missed or its confirmation mail was not read. That makes the table above a faster diagnostic than replaying blindly.
Flag 1 — Chapter 4
Kurisu, subject Did you write it?
| Step | You see | Reply |
|---|---|---|
| 1 | Did you write it? | Scientist |
| 2 | Scientist?? | Bad scientist |
| 3 | Bad scientist. | Dad joke |
| 4 | Home Alone. | Outsider |
| 5 | Ehhh? | Disgrace |
| 6 | Staring at my hand. | Why am I still here? |
| 7 | Being here | Read it — Flag 1 |
Also grants Genius Girl’s Melancholy.
Flag 2 — Chapter 5
Plans → Traveling expenses. Read the later Idiot! mail, then read ( ´ · ω · \)` — that received mail is Flag 2.
Flag 3 — Chapter 7
The key (ﾉД \)→I don’t have a key→ emoji subject( ° д ° )→Security→You’re delusional, I know.→Reality→ readReality` (Flag 3).
Need Flags 1–2 if you also want Gero Froggy on a side save. From this same The key mail, Frog is the collectible path, not the flag path.
Flag 4 — Chapter 8
Explain yourself! — only one reply. Later read From an unpopular girl (Flag 4).
Flag 5 — Chapter 9
Contact me, idiot! → Worried. Read Re: Re: Contact me, idiot! (Flag 5).
Flag 6 — Chapter 10 (save required)
Mid-chapter Kurisu mail Where are you now?
- Ignore it to stay on Kurisu’s ending (Paradox Meltdown).
- Reload and reply
Where you arefor Flag 6, then the true ending.
Chapter 10 still plays like Kurisu’s route through the credits; the true ending continues after. Then wait on the black screen — secret scene.
Story explanation — spoilers
The six flags are the “make friends with Kurisu over email” throughline. They do not skip the Chapter 6–9 worldline branches; you still have to send each D-Mail / call the PhoneWave to reach Chapter 10. Moeka’s new route is the Chapter 9 stop, not a true-ending requirement.
Verification after the September 7 update
The official September 7, 2026 Steam update addresses a Steam Deck audio issue and ongoing Steam Machine compatibility work. It does not announce changes to Kurisu’s six-email flag chain or the Chapter 10 split. On September 15, the flag order, confirmation mails, and Kurisu/True split were rechecked against the current Kiri Kiri Basara 100% guide and the live Steam achievement list.
Last verified: September 15, 2026. Steam app 4012810. Uncertain items are marked not yet confirmed.
Sources
- Kiri Kiri Basara 100% Guide (Martin, 19 Aug 2026)
- Kiri Kiri Basara review (13 Aug 2026)
- Kiri Kiri Basara Digital Deluxe review (15 Aug 2026)
- Official English site
- Steam store
- Steam achievements
- Steam Community — September 7 update
- Videos used as research (facts extracted, not copied): KKB 100% Guide, KKB review, Noisy Pixel review
STEINSGATEREBOOT.site is an unofficial fan-made guide and is not affiliated with MAGES., Spike Chunsoft, or the game’s rights holders.