Editing Battle of Tsushima (section)

===Salvo firing director system===
{{Further|Ship gun fire-control system#Pre-dreadnought control system}}

Up to the [[Battle of the Yellow Sea]] on 10 August 1904, naval guns were controlled locally by a [[gunnery officer]] assigned to that gun or a turret. He specified the elevation and deflection figures, gave the firing order while keeping his eyes on the [[inclinometer]]s indicating the rolling and pitching angles of the ship, received the fall of shot observation report from the spotter on the mast, calculated the new elevation and deflection to 'walk' the shots in on the target for the next round, without much means to discern or measure the movements of his own ship and the target. He typically had a view on the horizon, but with the new 12-inch gun's range extended to over {{convert|8|mi|km}}, his vantage point was lower than desired.<ref>{{cite journal|journal=Naval War College Review|issue=Spring 2005|volume=58, No.2|last=Koda|first=Yoji|title=The Russo-Japanese War: Primary Causes of Japanese Success|date=25 April 2024 |url=https://www.jstor.org/stable/26394181|pages=KODA 34–35|jstor=26394181|access-date=19 April 2024}}</ref>{{efn|1=Approximate distance to horizon is calculated by sqrt(2 x ''h'' x ''R'') where ''R'' is the [[Earth radius]] and ''h'' is the observation height above the sealevel. (see [[horizon]] for details.) Using battleship ''Mikasa'' as the example, the height of gunsight on top of 12" main gun turret (technically they are barbettes with armoured covers that make them look like turrets) is about 10 to 11m from the waterline and the bridge height is about 16 to 18m from the waterline by estimating from the [[:File:Battleship Mikasa from JFS1906 Cropped.png|sideview plan]]. Using the globally-averaged earth radius of 6,371,000m<ref>{{cite web|title=Earth Fact Sheet|author=NASA|url=https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html}}</ref> for the ''R'', the distance observable from the turret is sqrt(2 x 11 x 6371000m) = 11.8km. The distance observable from the bridge is sqrt(2 x 16 x 6371000m) = 14.3km. Mikasa's main guns had a range of 14km. <small>(This explanatory note is provided for the benefit of the readers in accordance with [[WP:CALC]].)</small>}}

In the months before the battle, the Chief Gunnery Officer of ''Asahi'', Lieutenant Commander [[Kanji Kato|Katō Hiroharu]], aided by a Royal Navy advisor who introduced him to the use of the early mechanical computer [[Dumaresq]] in fire control, introduced a system for centrally issuing the gun-laying{{efn|What ship to target, and the distance to the target were specified on the bridge. Each gun/turret aimed the target to determine the deflection, and used a distance-to-elevation conversion table for the gun to set the elevation.}} and salvo-firing orders by voice.{{efn|All the gunnery personnel on ''Mikasa'' was given a lecture on telephone systems at 17:20 on 18 April 1905 in Chinhae Bay.<ref>{{cite web|editor=Navy General Staff|date=18 April 1905|title=Battleship Mikasa Wartime Daily Log 3(7)|url=https://www.jacar.archives.go.jp/aj/meta/listPhoto?LANG=default&BID=F2009052815372931381&ID=M2009052815373031389&REFCODE=C09050340000|page=0339|access-date=16 April 2024|language=ja}}</ref>}} Using a central system allowed the spotter to identify a salvo of distant shell splashes much more effectively than trying to identify a single splash among the many in the confusion of fleet-to-fleet combat. Further, the spotter needed to keep track of just one firing at a time as opposed to multiple shots on multiple stopwatches, in addition to having to report to just one officer on the bridge. The 'director' officer on the bridge had the advantage of having a higher vantage point than in the gun turrets, in addition to being steps away from the ship commander giving orders to change the course and the speed in response to the incoming reports on target movements.<ref name=salvo>{{cite web|editor=Navy General Staff|date=17 April 1905|title=Battleship Mikasa Wartime Daily Log 3(7)|url=https://www.jacar.archives.go.jp/aj/meta/listPhoto?LANG=default&BID=F2009052815372931381&ID=M2009052815373031389&REFCODE=C09050340000|pages=0336–0337|access-date=16 April 2024|language=ja}}</ref>

This fire control director system was introduced to other ships in the fleet, and the training and practice on this system were carried out in the months waiting for the arrival of the Baltic Fleet{{efn|name=subc}}{{efn|name=practice|During the 11 days from 28 March to 7 April 1905, ''Mikasa'' had 5 days with gunnery training sessions.  In these 5 days, ''Mikasa'' fired 9,066 rounds of practice ammunition.}} while its progress was reported by the British intelligence from their naval stations at [[Gibraltar]], [[Mediterranean Fleet|Malta]], [[Aden Colony|Aden]] ([[Yemen]]), [[Naval Base Simon's Town|Cape of Good Hope]], [[East Indies Station|Trincomalee]] ([[Sri Lanka|Ceylon]]), [[China Station|Singapore]] and [[British Forces Overseas Hong Kong|Hong Kong]], among other locations.{{sfn|British Assistance|1980}}

As a result, Japanese fire was more accurate in the far range ({{convert|3|to|8|mi|km|disp=or|0}}),{{efn|On 6-7 April 1905, ''Mikasa'' conducted the second sub-calibre gunnery training competition against ''Shikishima''. ''Mikasa'' scored 285 hits / 927 shots (30.7%), ''Shikishima'' scored 258/974 (26.5% hitrate) on opposite course; ''Mikasa'' scored 894/1703 (52.5%), ''Shikishima'' scored 1085/1672 (64.9%) on the same course with the target at the distance of 280–720 m at 6 knots, with towed target by torpedo-boat at 6 knots.<ref>{{cite web|editor=Navy General Staff|date=7 April 1905|title=Battleship Mikasa Wartime Daily Log 3(6)|url=https://www.jacar.archives.go.jp/aj/meta/listPhoto?LANG=default&BID=F2009052815372931381&ID=M2009052815373031388&REFCODE=C09050339900|pages=0289–0296|access-date=15 April 2024|language=ja}}</ref>}} on top of the advantage they held in the shorter distances using the latest 1903 issue [[Barr and Stroud]] FA3 [[coincidence rangefinder]]s of baselength {{cvt|5|ft|m}},{{efn|Baselength is the distance between the left and the right lens or mirror facing the target, which largely determines the effective range of a rangefinder.}}  which had a range of {{convert|6000|yd|m}}, while the Russian battleships were equipped with ''Lugeol'' [[Stadiametric rangefinding|stadiametric rangefinders]] from the 1880s (except battleships ''Oslyabya'' and ''Navarin'', which had the Barr and Stroud 1895 issue FA2 of baselength {{cvt|4.5|ft|m}} retrofitted), which only had a range of about {{convert|4000|m|yd|order=flip}}.{{sfn|Forczyk|2009|pages=56–57}}