Night Zuiun Cutin Test (June 2023)

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1	Data from TsunDB. Samples with historical ships/gears are removed unless specified otherwise.
2	This is joint work with fourinone.
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4	In this test, we look at night zuiun cutin (NZCI) and other cutins in the game. Our findings are listed below.
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6	1. NZCI trigger rate formula
7	We find NZCI has the following trigger rate formula:
8	If luck < 50: [base value] = FLOOR(15 + [luck] + 0.75 * sqrt([level]) + [modifiers])
9	If luck >= 50: [base value] = FLOOR(65 + sqrt([luck]-50) + 0.8 * sqrt([level]) + [modifiers])
10	[trigger rate] = [base value] / [type mod]
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12	where modifiers are as follows
13	Condition	Modifier
14	Flagship	15
15	Triggered searchlight	-10
16	Triggered starshell AND/OR triggered NZCI	-10
17	Has Skilled Lookout	8
18	Has Torpedo Squadron Skilled Lookout	0
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20	and [type mod] = 135.
21	Please note that this formula only applies to single-roll NZCI (2 guns, 1 night Zuiun, no radar).
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24	2. Torpedo squadron skilled lookout (TSSLO) for other cutins
25	We find that the earlier estimated bonus (+9 base value for DD/CL(T); +5 base value for CA(V)) is inaccurate due to problems in the submitted data.
26	The new estimated bonus is +8 base value for DD/CL(T) and +0 for other ship types.
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28	Earlier test: https://twitter.com/Divinity_123/status/1479343019379802112
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31	3. Trigger rate for other friendly cutins after NZCI
32	We find that friendly cutins after NZCI have a +5~+8 base value. This bonus does not stack with the bonus from star shell.
33	When NZCI and star shell are both triggered, the base value bonus for subsequent cutins is likely the same as the bonus with NZCI.
34	The base value bonus may be +4 (same as that for star shell). It is not clear why our estimation is off for now. We will update the results if we have new findings.
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37	4. Trigger rate for other Abyssal cutins after NZCI
38	We find that Abyssal cutins after NZCI have a -10 base value. This bonus does not stack with the bonus from star shell.
39	When NZCI and star shell are both triggered, the base value bonus for subsequent cutins is likely the same as the bonus with NZCI.
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42	5. Accuracy bonus for NZCI
43	NZCI has 1.02~1.11 accuracy bonus. See the night hit rate formula test for more details:
44	https://docs.google.com/spreadsheets/d/183MFdMfBS7Oc3doCZYyI-R1jxDaCZ-Y9wMt_HW8PFEg/edit?usp=sharing
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47	6. Accuracy bonus for other friendly attacks after NZCI
48	NZCI provides the same accuracy bonus as a star shell. See the night battle hit rate formula test for more details:
49	https://docs.google.com/spreadsheets/d/183MFdMfBS7Oc3doCZYyI-R1jxDaCZ-Y9wMt_HW8PFEg/edit?usp=sharing
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52	7. Multi-roll NZCIs
53	When equipping more than one night Zuiun and/or radar, it was suspected that the trigger rate follows a multi-roll model where each NZCI setup is checked sequentially for CI trigger.
54	The multi-roll model (assuming [type mode] = 135 for all NZCI setups) slightly underestimates the data. We do not have enough data to work out the reason yet.
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