Question: What was name of the most important land tax upheld by feudalism under the king?

Context paragraphs:
No Land Tax Campaign: The No Land Tax Campaign was a minor Australian political party formed prior to the 2015 New South Wales state election.  It was formed in opposition to the levying of land tax, which in New South Wales applies to investment properties and holiday homes.

English Land Tax: The English land tax was a national property tax introduced by Parliament in 1692.  The tax was levied on rental values and applied both to rural and to urban land.  No provision was made for re-assessing the 1692 valuations and consequently they remained in force well into the 18th century.

Rai people: The Khambu or Rai are indigenous ethnolinguistic groups of Nepal, the Indian State of Sikkim and Darjeeling Hills.  They were Rai meaning king (Rai means King in old Khas kura (Nepali).  When the king Prithvi Narayan Shah couldn't defeat Khambu king, he somehow took them in confidence that the land is theirs forever and gave them the title Rai in around B.S. 1832 .  The title of Rai instead "khambu" kirant people who used to live in majh kirant for particular reason.  The Rai are the Khambu.  Then the post Rai was provided to the topmost leaders of the region.  They were given the power to collect land tax.  That's why sometimes Rai people are called "Jimee" or "Jimee-wal".  The Rai belong to the Kirati group or the Kirat confederaticludes Limbu, Sunuwar, Yakkha and Dhimal ethnic groups.  Sonjal Rai was one of the most notorious warriors in the Gurkha tribe.

Hide (unit): The hide was an English unit of land measurement originally intended to represent the amount of land sufficient to support a household.  It was traditionally taken to be 120 acre , but was in fact a measure of value and tax assessment, including obligations for food-rent ("feorm "), maintenance and repair of bridges and fortifications, manpower for the army ("fyrd "), and (eventually) the "geld " land tax.  The hide's method of calculation is now obscure: different properties with the same hidage could vary greatly in extent even in the same county.  Following the Norman Conquest of England, the hidage assessments were recorded in the Domesday Book and there was a tendency for land producing £1 of income per year to be assessed at 1 hide.  The Norman kings continued to use the unit for their tax assessments until the end of the 12th century.

Taxation in premodern China: In the premodern era of Chinese history, taxation by the various dynasties that ruled China varied greatly.  Overall, the most important source of state revenue was the tax on agriculture, or land tax.  During some dynasties, the government also imposed state monopolies which became important sources of revenue for the government.  The monopoly on salt was especially lucrative and stable.  Commercial taxes were generally quite low, except in times of war.  Other means of state revenues consisted of inflation, forced labor (the corvee), and expropriation of rich merchants and landowners.  Below is a chart of the sources of state revenue in Imperial China.

Land and Buildings Transaction Tax: Land and Buildings Transaction Tax (LBTT) is a tax charged in Scotland.  It replaced the United Kingdom Stamp Duty Land Tax (SDLT) from 1 April 2015.

Taxation in medieval England: Taxation in medieval England was the system of raising money for royal and governmental expenses.  During the Anglo-Saxon period, the main forms of taxation were land taxes, although custom duties and fees to mint coins were also imposed.  The most important tax of the late Anglo-Saxon period was the geld, a land tax first regularly collected in 1012 to pay for mercenaries.  After the Norman Conquest of England in 1066, the geld continued to be collected until 1162, but it was eventually replaced with taxes on personal property and income.

Fair Land Tax – Tax Party: The Fair Land Tax – Tax Party is a registered minor political party in South Australia led by Andrew Desyllas.  Its platform consists of more favourable land tax rates.  It ran at the 2010 state election with negligible results.  The party contested the 2014 state election again with negligible results.

Scutage: Scutage is a medieval English tax levied on holders of a knight's fee under the feudal land tenure of knight-service.  Under feudalism the king, through his vassals, provided land to knights for their support.  The knights owed the king military service in return.  The knights were allowed to "buy out" of the military service by paying scutage.  As time passed the king began to impose a scutage on holders knight's fees, even in time of peace.

Tallage: Tallage or talliage (from the French "tailler, i.e. " a part cut out of the whole) may have signified at first any tax, but became in England and France a land use or land tenure tax.  Later in England it was further limited to assessments by the crown upon cities, boroughs, and royal domains.  In effect, tallage was a land tax.

Supporting paragraphs: Scutage Taxation in medieval England
Answer: geld