Arknights: Heart Of Surging Flame Retrospection (Rerun) Event Operations And Farming Guide

Details of the Event Operations can be seen in the sections below the farming guides.

TLDR Farming Guide:

• Make sure all Event Operations and Challenges have been cleared once for First-Clear rewards.
• Farm OF-7 until you have farmed 1060 [Siesta Obsidian] using ~530 Sanity.  Don't over-farm [Siesta Obsidian]. To get this exactly, run:
  • For New Players:
    • OF-1, OF-3, OF-4, OF-6: 1 time (first clear only)
    • OF-2: 3 times (first clear + 2 more times)
    • OF-7: 15 times (first clear + 14 more times)
  • For Returning Players:
    • OF-7: 17 times (1020 Obsidian)
    • OF-6: 1 time (28 Obsidian + 7 Tickets)
    • OF-1: 1 time (12 Obsidian + 3 Tickets)
• Farm OF-8 40 times (32 times for new players) with 1200 Sanity (940 for new players) to get 600 [Obsidian Festival Ticket] (470 for new players). (NOTE: since the number of Tokens you get from OF stages are variable, you may need more or less runs depending on your luck)
• Farm OF-F4 ~35 (~32 for new players) times with [Obsidian Festival Ticket] to get 2800 (2560 for new players) [Obsidian Festival Token] for the Capsule Machines. (NOTE: since the number of Tokens you get from OF stages are variable, you may need more or less runs depending on your luck)
• If you are new/low level, all OF stages give the same Obsidian/Ticket per sanity, higher sanity stages just make faster farming.  OF-F3 is the same Token per ticket ratio as OF-F4, just slower farming.
• The order you wish to farm the Event currency is up to you.
• Pure f2p will Definitely have enough Sanity to clear both shops + Weekly Annihilation, so no worries!
• There is NO infinite machine for the rerun.

For details, check the "Detailed Farming Guide" section, and please let me know in the comments or via Discord if you see any errors in my math.

Detailed Farming Guide

There are two main Event Currencies for [Heart of Surging Flame Retrospection]

• [Siesta Obsidian] - Players collect rewards based on total accumulated [Siesta Obsidian] via a rewards ladder.  [Siesta Obsidian] is awarded for completing certain Event Operations.  You only want enough [Siesta Obsidian] to clear the Event ladder, and no more. 1060 [Siesta Obsidian] to clear the Ladder are all that are necessary.
  • Event Operations award 2 [Siesta Obsidian] per sanity spent, though some Operations award a mix of [Siesta Obsidian] and [Obsidian Festival Ticket].  This means 530 Sanity on Operations is needed to clear the Ladder. 
  • OF-7 is the fastest node for farming [Siesta Obsidian], costing 30 sanity and giving 60 [Siesta Obsidian]. 
  • To get 1060 [Siesta Obsidian] exactly run:
    • For New Players:
      • OF-1, OF-3, OF-4, OF-6: 1 time (first clear only)
      • OF-2: 3 times (first clear + 2 more times)
      • OF-7: 15 times (first clear + 14 more times)
    • For Returning Players:
      • OF-7: 17 times (1020 Obsidian)
      • OF-6: 1 time (28 Obsidian + 7 Tickets)
      • OF-1: 1 time (12 Obsidian + 3 Tickets)
• [Obsidian Festival Ticket] - Players spend [Obsidian Festival Ticket] instead of Sanity to run the [Fairground] Event Operations, which award [Obsidian Festival Token].  [Obsidian Festival Token] are then used to make pulls on the Capsule Machines to gain rewards.  It costs 200 [Obsidian Festival Token] for a 10 pull, and there are 32 items per box, so it costs 640 [Obsidian Festival Token] to clear each box.  Since there are 5 Boxes, it requires 3,200 [Obsidian Festival Token] for all Boxes to be cleared.
  • 400 [Obsidian Festival Token] are gained through the [Siesta Obsidian] ladder reward, leaving 2,800 [Obsidian Festival Token] to Event Operations.
  • For new players who have not yet cleared them, 240 [Obsidian Festival Token] are awarded by first-clear of the [Fairground] and [Challenge] Operations.
  • The most efficient Operation to farm [Obsidian Festival Token] is OF-F4, which awards on average 4 [Obsidian Festival Token] per [Obsidian Festival Ticket] spent.  This means 700 (640 for new players) [Obsidian Festival Ticket]  is needed to clear the limited Capsule Machines.
  • 100 [Obsidian Festival Ticket are gained through the [Siesta Obsidian] ladder reward, leaving 600 (540 for new players) [Obsidian Festival Ticket] to Event Operations.
  • For new players who have not yet cleared them, 70 [Obsidian Festival Ticket] are awarded for Operation First-Clear rewards
  • Normal Event Operations award .5 [Obsidian Festival Ticket] per sanity spent, though some Operations award a mix of [Siesta Obsidian] and [Obsidian Festival Ticket].  This means 1200 (940 for new payers) Sanity on Operations is needed to clear the limited Capsule Machines. 
  • OF-8 is the fastest node to farm [Obsidian Festival Ticket], costing 30 Sanity and giving 15 [Obsidian Festival Ticket]
  • OF-F4 is the fastest node to farm [Obsidian Festival Token], costing 20 [Obsidian Festival Ticket] and giving 79-81 [Obsidian Festival Token].
• Total Sanity required for first clears of EX and Challenge is 120.  Total sanity required to clear the [Siesta Obsidian] reward ladder and the limited Capsule Machines is 530 + 1200 = 1730 Sanity to clear all shops. So 1730/(less for new players) Total sanity needed, which comes out to 173 Sanity per day for the 10 day event.  
• Natural sanity regen is 240 per day, which means there will be no problem clearing this event.

See something wrong with my math?  Let me know in the comments below or DM me in Discord.

Event progress will be saved from the previous run.  This means no first clear rewards will be available for any Stages the player cleared on the original run of the event.  Any stages not cleared on the previous run will have first-clear rewards available"

The only new Stage added for the rerun is OF-ST6.

Trust Bonus Operators

EX Stages are available immediately at the start of the event.

Challenge Conditions:

• OF-EX1 - Enemy ranged units have significantly increase range.
• OF-EX2 - Enemies have significantly higher DEF.
• OF-EX3 - Enemies have significantly higher ASPD.
• OF-EX4 - Medic Operators cost three times as much to deploy.
• OF-EX5 - Deployment Points regenerate 66% slower.
• OF-EX6 - Number of available Roadblocks is reduced by 50%.