Le pion est sur la case.

Because pion is a masculine noun, so it takes le, and case is a feminine noun, so it takes la.

In French, every noun has a grammatical gender:

• le pion = the pawn / the token
• la case = the square / the space

This gender is grammatical, not necessarily logical or physical.

Here, pion usually means pawn, counter, or playing piece, depending on context.

For example:

• in chess, un pion = a pawn
• in a board game, un pion = a token or playing piece

So in this sentence, it refers to some game piece placed on a square.

No, not usually.

In this sentence, case means square, space, or box on a board, grid, or form. It does not mean a legal case or a suitcase.

So:

• la case = the square / the space

This is a very common false friend for English speakers.

Because the subject is Le pion, which is third person singular: it.

The verb être = to be, and its present-tense forms include:

• je suis = I am
• tu es = you are
• il / elle est = he / she / it is
• nous sommes = we are
• vous êtes = you are
• ils / elles sont = they are

So:

• Le pion est... = The pawn is...

Sur means on or on top of.

So:

• sur la case = on the square

It is the natural preposition when something is physically positioned on a surface or on a marked space.

Because this sentence follows a very common French pattern that matches English closely:

subject + verb + prepositional phrase

So:

• Le pion = subject
• est = verb
• sur la case = where it is

French and English often use the same basic order in simple statements like this.

Because la case begins with a consonant sound, so you keep la.

You only use l’ before a vowel sound or silent h:

• la case
• l’école
• l’hôtel

Also, sur + la does not contract. French contractions happen with certain prepositions like:

• à + le = au
• de + le = du

But not with sur.

A simple pronunciation guide is:

luh pyon eh sur lah kahss

A few notes:

• le is often pronounced like luh
• pion sounds roughly like pyon
• est is pronounced like eh
• sur has a French u sound, which English speakers often find tricky
• case sounds like kahz or kahss, depending on accent

Also, the final t in est is silent.

Case is generally a feminine noun, so you normally say:

• la case
• une case

That is the noun’s usual grammatical gender.

Usually, sur la case is better for a board-game square.

• sur la case = on the square
• dans la case = in the box / inside the square

If you are talking about a game board, French commonly uses sur because the piece is resting on the board surface. Dans la case can sometimes be used, but it suggests being inside a box-like area more strongly.

Le pion means the pawn / the piece, while un pion means a pawn / a piece.

So the difference is:

• Le pion est sur la case. = The pawn is on the square.
• Un pion est sur la case. = A pawn is on the square.

French uses articles very regularly, so in most cases you need one before the noun.