Það var sigurvegarinn sem færði leikpeðið á síðasta reitinn.

This is a very common Icelandic emphasis pattern, often called a cleft sentence.

The structure is:

Það var X sem Y = It was X that/who Y

So:

Það var sigurvegarinn sem færði leikpeðið á síðasta reitinn means something like:

It was the winner who moved the game piece to the last square

The point of this structure is to emphasize sigurvegarinn. A less emphatic version would be:

Sigurvegarinn færði leikpeðið á síðasta reitinn.

In this sentence, það does not refer to a specific thing. It is just part of the cleft construction.

Sigurvegarinn means the winner.

It is built from:

• sigurvegari = winner
• -inn = the suffixed definite article

So:

• sigurvegari = a winner
• sigurvegarinn = the winner

Here it is masculine singular nominative.

That is one of the basic features of Icelandic grammar: the definite article is usually a suffix, not a separate word like English the.

So:

• sigurvegari = winner

• sigurvegarinn = the winner

• reitur = square, space, cell

• reitinn = the square

• leikpeð = game piece
• leikpeðið = the game piece

English uses a separate article, but Icelandic usually builds definiteness directly into the noun.

Here sem introduces the relative clause and means who or that in English.

So:

sigurvegarinn sem færði leikpeðið = the winner who moved the game piece

In this kind of sentence, sem is the normal word to use after the emphasized element in a cleft construction.

A useful thing to remember is that sem does not change form for gender, number, or case.

Færði is the past tense of the verb færa.

færa often means:

• to move
• to bring
• to shift
• to place forward

In this sentence, it means moved.

So:

• færa = to move
• færði = moved

It is the form used here because the sentence is in the past: the moving already happened.

Here is the case structure:

• sigurvegarinn — nominative
  It is the subject of the action.

• leikpeðið — accusative
  It is the direct object, the thing being moved.

• á síðasta reitinn — accusative after the preposition á
  This shows movement to/onto the last square.

So the sentence is a good example of Icelandic case marking: subject in nominative, direct object in accusative, and destination also in accusative after á.

Because á takes different cases depending on meaning:

• accusative for motion toward a place
• dative for location in/on a place

Here the piece is being moved onto/to the last square, so Icelandic uses the accusative:

• á síðasta reitinn = onto the last square

If you were describing where something already is, you would use the dative instead:

• á síðasta reitnum = on the last square

This motion-vs-location contrast is very important with Icelandic prepositions.

Síðasta is the adjective síðastur meaning last, but here it appears in its weak form.

Why weak?

Because it comes before a definite noun:

• reitinn = the square

In Icelandic, adjectives are often:

• strong when the noun is indefinite
• weak when the noun is definite

So compare:

• á síðasta reitinn = onto the last square
• á síðastan reit = onto a last square

The second version is not very natural in meaning here, but it shows the contrast in form.

Because leikpeð is a neuter noun, and many neuter nouns have the same form in nominative and accusative singular.

So:

• leikpeðið can be nominative definite singular
• leikpeðið can also be accusative definite singular

In this sentence, its job tells you the case: it is the thing being moved, so it is the direct object, which makes it accusative.

This is very common in Icelandic: sometimes the form alone does not show the case clearly, so you also use sentence structure and verb function.

Literally, yes, but functionally not always.

In a sentence like this, það is mostly a structural word used to build the cleft sentence. In natural English, you often do translate it as it:

It was the winner who moved the game piece...

But it does not refer to a concrete thing. It is closer to the dummy it in English expressions like:

• It is important
• It was John who called

So yes, it looks like it, but its role is grammatical rather than referential.

You would simply say:

Sigurvegarinn færði leikpeðið á síðasta reitinn.

That is the straightforward, non-cleft version:

• Sigurvegarinn = the winner
• færði = moved
• leikpeðið = the game piece
• á síðasta reitinn = to/onto the last square

The original sentence puts extra focus on the winner as the person who did it.

Very roughly:

• þ is like the th in thin
• ð is like the th in this

So Það begins with a th sound.

However, final ð in Icelandic is often pronounced weakly, and in normal speech það can sound softer than an English learner expects.

A rough learner-friendly approximation is:

thahth or even thah

The exact pronunciation depends on speaking style, but the important thing is:

• start with voiceless th for þ
• recognize that final ð is often not strongly pronounced