A railway gun, also called a railroad gun, is a large artillery piece, often surplus naval artillery, mounted on, transported by, and fired from a specially designed railway wagon.
 Many countries have built railway guns, but the best known are the large Krupp-built pieces used by Germany in World War I and World War II.
 Smaller guns were often part of an armoured train.
Sakan Ryokan or "Hotel Sakan" (ホテル佐勘) is an historic ryokan (Japanese inn) located in Sendai, Miyagi Prefecture, Japan.
 The inn is over 1,000 years old, and is located within the spa resort named "Akiu Spa," which has four communal onsen (baths) that are supplied by natural hot springs.
 The hot springs are one of the three oldest ones in Japan, and are located near the Natori River.
 The inn was originally started by a man named Kanzaburo Satoh, whom the inn is named after.
 Ownership of the inn has been handed down to Satoh's descendants for 34 generations.
 It is located next to the 400 year old Iwanumaya Hotel.
The 21 cm Schnelladekanone Länge 45, abbreviated as 21 cm SK L/45 was a German naval gun developed in the years before World War I that armed the armored cruiser SMS Blücher of the Imperial German Navy.
 During World War I spare guns were converted to railway guns and later employed as coastal artillery during World War II.
Erfurter Maschinenfabrik (ERMA) was a German weapons manufacturer founded in 1922 by Berthold Geipel.
 Prior to and during World War II it manufactured many firearms, including the K98k, MP40, and several other submachine guns.
S. Howard Voshell (1888–1937) was an American tennis player and later a promoter.
 He was an insurance broker.
 In world war 1, Voshell attained the rank of second Lieutenant in the air service.
 Voshell was a left-hander with a "cannon ball serve" and sent down many aces with it.
 Voshell made his debut in the U. S. Championships in 1910 and lost his first match.
 He had early round losses in 1912, 1913, 1914, 1915, 1916 and 1917.
 In 1917 and 1918 he won the National Indoor championships.
 At the 1918 U. S. championships, Voshell beat 15 year old prodigy Vincent Richards and Craig Biddle before losing to Robert Lindley Murray.
 Every year from 1919 to 1926, Voshell lost early at the U. S. Championships.
 He retired in 1930.
 Voshell persuaded Fred Perry to turn pro and was co-promoter (with Frank Hunter) of the early pro matches between Perry and Vines in 1937.
 His health deteriorated as the year wore on and he died in November 1937 aged 49.
The Krepost Sveaborg was an Imperial Russian system of land and coastal fortifications constructed around Helsinki during the First World War.
 The purpose of the fortress was to provide a secure naval base for the Russian Baltic fleet and to protect Helsinki and block routes to Saint Petersburg from a possible German invasion.
 Krepost Sveaborg was part of Peter the Great's Naval Fortress, a coastal fortification system protecting access to Saint Petersburg by sea.
 The central part of Krepost Sveaborg was the old fortress of Suomenlinna where the fortress headquarters were located.
 Due to technological advances in artillery the old fortress was no longer capable of providing a sufficient protection, and a new main defensive line was built well beyond the old fortress boundaries.
 New coastal artillery guns built on outlying islands protected Krepost Sveaborg from the sea, while fortified lines constructed around Helsinki were intended to stop any attacks on land.
 The primary coastal guns were 10 in model 1891 guns and 6 in model 1892 Canet guns. Older 11 in model 1877 guns were also used.
 In summer 1917 the fortress had two hundred coastal or anti-landing guns, of which 24 were 10-inch guns in six batteries, 16 were 6-inch Canet guns in four batteries and twelve were 11-inch guns in three batteries.
 The artillery used in land fortifications included older coastal guns, old fixed carriage guns and newer light field guns.
 In March 1917, Krepost Sveaborg had a total of 463 guns, although many of them were obsolescent.
 Krepost Sveaborg was still partly incomplete in 1917 when the February Revolution halted most of the construction work.
 Some further construction work was carried out during the remaining year, but all work halted during the October Revolution.
 Following the Finnish Declaration of Independence, parts of the land fortifications were used in the Finnish Civil War.
 The coastal fortifications were later taken over by Finland to protect Helsinki, while the land fortifications were mostly abandoned and disarmed.
James Zimmermann (1886–1917) was a British tennis player in the years before World war 1.
 His father was German and James was embarrassed by his German name, so he abbreviated his surname to Mann.
 Zimmermann reached the quarter finals of the Wimbledon men's singles in 1912 (where he lost to Alfred Beamish).
 He lost in the second round at Wimbledon in 1913.
 According to his obituary in the Sydney newspaper "Referee" on 17 October 1917, Zimmermann was "always popular with the crowd, for his garrulity on court, though sometimes disconcerting to his opponents, he had a vein of humour and irresponsibility".
 In 1915 his habit of sleepwalking led him into danger, when he was found wandering on the Brighton railway line near Victoria station (he was sentenced to six months imprisonment, though the sentence was quashed on appeal).
 In World War 1, Zimmermann was a sergeant in the H. A. C. and died from wounds sustained in action in 1917.
The 21 cm Schnelladekanone Länge 40, abbreviated as 21 cm SK L / 40, was a German naval gun developed in the years before World War I that armed a number of the Imperial German Navy's protected and armored cruisers. Later spare guns were adapted to railway guns during World War I and later employed as coastal artillery during World War II.
World War 1 in Colour is a documentary narrated by Kenneth Branagh.
 The first of its six parts aired on 23 July 2003 in the United Kingdom.
 It was released on DVD in the United States as "World War 1 in Color" on 10 May 2005.
 The documentary consists of colourised footage from World War I.
The Krupp family (see pronunciation), a prominent 400-year-old German dynasty from Essen, have become famous for their production of steel, artillery, ammunition, and other armaments.
 The family business, known as Friedrich Krupp AG, was the largest company in Europe at the beginning of the 20th century.
 It was important to weapons development and production in both world wars.
 One of the most powerful dynasties in European history, for 400 years Krupp flourished as the premier weapons manufacturer for Germany.
 From the Thirty Years' War until the end of the Second World War, they produced everything from battleships, U-boats, tanks, howitzers, guns, utilities, and hundreds of other commodities.

Question: What 400 year old German company was the premier weapons manufacturer for railway guns in World War 1 & 2?
Answer: Krupp