Here's a short story:

The term high definition once described a series of television systems originating from August 1936; however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30 lines of resolution. The ongoing competition between companies and nations to create true "HDTV" spanned the entire 20th century, as each new system became more HD than the last.In the beginning of the 21st century, this race has continued with 4k, 5k and current 8K systems. 

The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems. The Baird system was discontinued in February 1937. In 1938 France followed with their own 441-line system, variants of which were also used by a number of other countries. The US NTSC 525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable. All of these systems used interlacing and a 4:3 aspect ratio except the 240-line system which was progressive (actually described at the time by the technically correct term "sequential") and the 405-line system which started as 5:4 and later changed to 4:3. The 405-line system adopted the (at that time) revolutionary idea of interlaced scanning to overcome the flicker problem of the 240-line with its 25 Hz frame rate. The 240-line system could have doubled its frame rate but this would have meant that the transmitted signal would have doubled in bandwidth, an unacceptable option as the video baseband bandwidth was required to be not more than 3 MHz. (End of story)

Provide your best guess for the following question. Give ONLY the guess, no other words or explanation.

For example:

Guess: <most likely guess, as short as possible; not a complete sentence, just the guess!>

Here are a few examples of questions and answers:

Question: What can't the video baseband bandwidth be more than?
Guess: 3 MHz

Question: Whose high-definition TV service first started trials?
Guess: The British high-definition TV service

Question: When?
Guess: August 1936

Question: When did regular service start?
Guess: 2 November 1936

Question: What did high definition originally describe?
Guess: A series of television systems

Question: How many lines of resolution did they have?
Guess: 30

Question: What drove companies and nations to create true HDTV?
Guess: Competition

Question: How long did that competition last?
Guess: The entire 20th century

Now answer the following question in the same format.

Question: What is the most current system?

8K systems.