Will the sasine register for a particular year show all the owners in that year?
No. The most common misconception about the register of sasines is that it can tell you who owned a particular property in a given year. The register is a record of property transfers rather than an ownership of every property at any given time. For example, if someone owned land in 1750 but actually bought or inherited it earlier, this will not appear in the register for 1750. It will appear in the register for the year in which they acquired it.
Finding tenants
Sasines are about owners and have little or nothing to say about cottars or tenants. Only after 1858 was it permissible, but not compulsory, to register long leases on properties. Consequently the register is of little use for identifying tenants.
Information about sizes and boundaries of properties
One of the prime functions of a sasine is to describe the property involved in a transaction. Acreages of properties are only rarely given before the appearance of Ordnance Survey maps from the mid-19th century. In the majority of cases, boundaries to properties are described in terms of the adjacent lands or in terms of geographical features (for example 'the lands of Y bounded by the river X on the east side, running north east up to the boundaries of the meadows of Z on the north side,' and so on).
As the 19th century wore on, more and more sasines refer to maps illustrating the property concerned. Some of these have been purposely preserved in the legal series of preservation writs held by NRS (reference RD16). Others can sometimes be found in local lawyers' offices, in other archives, and even in the NRS's own plans series (reference RHP). All too often, however, plans described in sasines no longer exist. They were routinely returned to the owner or the lawyers involved and subsequently lost. It is only with the development of photocopy technology in the early 1930s that plans of properties start to be recorded regularly in the registers with the associated sasines. There is a series of farm boundary plans compiled by the government during the late 1940s and early 1950s. These are preserved in the NRS plans series (reference RHP).
Other records showing Scottish landownership
Other records can sometimes give snapshots of who owned what at a given time. There were several poll and hearth taxes levied at the end of the 17th century. Similarly, Loretta Timperley used the surviving land tax records in the NRS to publish 'A Directory of Scottish Landownership in 1770' (Scottish Record Society, Edinburgh, 1976). This shows all the named landowners for that year together with the names and values of their properties, insofar as these can be gleaned from the record. This publication will be available in good reference libraries and it gives an accurate sense of the type of information available from the original record.
The annual valuation rolls from 1855 also list owners and occupiers (reference VR). The records of the Inland Revenue Valuation Office provide an overview of landownership in 1911-1912. Their staff surveyed every property in Scotland, recording the names of owners, tenants and occupiers, charges on the land, valuations and other particulars. Each property's boundaries and assessment number were marked on specially printed Ordnance Survey maps. The field books and maps resulting from this work are held by the NRS (reference IRS51-88 and IRS101-133).