Arknights "Yesterday's Sea" week-one timeline: 24 hours before launch to day 7, one move per day | GameHub

Arknights "Yesterday's Sea", 24 hours before launch: bank the sanity, nothing else

Don't drain your sanity this week. Daily stages run every day. Events don't.

Save three squad presets

Store a general squad that three-stars comfortably, a fast-clear single-DPS squad, and a low-investment fallback. On launch day you just load one, instead of building on the spot.

Don't spend materials early

Hold your LMD and chip catalysts. The shop usually discounts the same items, so spending early is spending twice.

Only trust the official notice

The site posted "SideStory 'Yesterday's Sea' limited event coming soon" on 2026-10-03. "Coming soon" means it hasn't started. Don't treat the announcement as a launch and go farm the wrong stages.

Arknights "Yesterday's Sea", launch day: how to split 240 sanity

Sanity regenerates at 1 point per 6 minutes. That's 1440 minutes a day, so 1440 ÷ 6 = 240. That's the daily ceiling, and it doesn't bank.

Spend the first 120 on first clears

First-clear rewards beat repeat farming. Clear the stages once on day one instead of immediately grinding the same one for drops.

Spend the second 120 on whatever you're shortest of

Short on chips? Farm chips. Short on EXP cards? Farm those. Splitting evenly leaves you short on everything.

Stay out of the hard stages on day one

Entering a hard stage underleveled costs you a full sanity bar per wipe. Clear what's stable on day one and leave the hard content for day 4 onward.

Arknights "Yesterday's Sea", days 2 to 3: the first two shop tiers

The buying order has exactly one test: can you still get this after the event ends? If not, it goes first.

Day	What to buy	Why it sits here
Day 2	Limited operator and potential materials	Gone when the event closes; the gap never fills
Day 3	Limited furniture and permits	One-time channel only
Day 4	Chip catalysts, dual chips	Slow to farm normally, better value during the event
Day 5 onward	EXP cards, LMD and other generic materials	Farmable any time, so they're the fallback

Don't grab LMD first on day 2

LMD is the easiest thing to buy by reflex because it always looks short. Short isn't urgent. It has other sources, so it goes later.

Clear your caps on day 3

Check your inventory caps before buying. Anything you're already maxed on is a wasted permit.

Arknights "Yesterday's Sea", days 4 to 5: levels and farming

These two days are the leveling window. The hard stages gate on investment, not on squad composition.

Drop a difficulty tier if you're underleveled

Farming the easier tier still pays materials and costs you nothing extra. Forcing the hard stage costs a whole sanity bar per wipe.

Three clean runs in a row is the bar

The test is blunt: run the same squad three times, no wipes. The reason it's three and not one: a run carried by luck drops below a coin flip when you repeat it.

Don't stack two DPS in one squad

Two damage dealers with nobody to break defense and the fight stalls. One DPS plus one utility slot is far steadier.

Arknights "Yesterday's Sea", days 6 to 7: clearing leftovers

The last two days are for settling up, not for starting new lines.

Work out what's still missing

List the materials you still need and divide by the drop per run to get the number of runs left. A big gap means prioritizing the limited tier.

Stop buying what's overflowing

If LMD is capped, walk away. Keep the permits for mastery materials instead.

Leave one bar of slack

Don't fill the last day. Keep one sanity bar in reserve for a sudden shortfall, like a material you're a handful short of.More information can be found in the Arknights guide.

Arknights "Yesterday's Sea": if you're stuck, start here (FAQ)

Is "Yesterday's Sea" a limited event?

A: Yes. The official site posted it as a limited SideStory coming soon on 2026-10-03, and the shop closes when the event ends, so limited items can't be recovered .

Should I bank sanity or spend it in week one?

A: Spend it on anything time-limited. You regenerate 240 points a day (1 per 6 minutes × 1440 minutes) and it caps at 240, so banking gains nothing.

When can I start the hard stages?

A: Day 4 or later. Use the first two days for first clears and materials, then go in once your investment is there. A wipe costs a full sanity bar.

Should I refill sanity at all?

A: One test only: is there a limited, non-refundable item left to buy? If yes, refill. If no, don't.

I'm a returning player. Which day do I join?

A: Day 4. Spend the first three days catching up on investment, because underleveled squads stall out later in the week regardless.

Scope note: Arknights publishes no version number, so figures follow in-game values and nothing here is guessed. Past event lists live in gghubs.com's guide section.