Can someone explain how a Stalemate happens in Chess thoroughly ? How many moves occur until a Stalemate ? Under what circumstances ?

A stalemate (or forced draw state) typically occurs under the following circumstances...

A) Player is NOT in check & is unable to make a legal move (most likely would place the player into check).

B) If the board is placed in the same state three times in a row (typically takes 6 turns to happen) -- This is known as the Threefold Repetition (aka the Three-peat) Rule. This draw is player-initiated.

C) 50 turns without any pieces being captured OR a pawn being moved. This count resets if any player moves a pawn OR captures a piece. -- This is known as the 50-move rule. FIDE (the international chess federation) has added a 75-move rule that makes it an automatic draw (instead of player-initiated).

D) Lack of "mateable" material for BOTH players -- A player cannot mate their opponent if they have only a knight OR a bishop (it's impossible to do so)... so if both players hit this state, you reach a stalemate automatically.

In timed games...

E) BOTH PLAYERS have exceed their allotted time with a "Sudden Death" time control (like "Game/30" or "SD/30" as an example) -- Normally, a player would lose if their opponent calls the game on time. HOWEVER, you could call your opponent if they're over as well. It's considered a draw as neither player could win the game within the allotted time.

If the game does NOT have a Sudden Death control in it (like 30/60... which is 30 moves in 60 minutes), it's possible to recover from exceed to your allotted time by hitting the move threshold (although the incurred deficit would be take out of your time allotment... so if you were 10 minutes over time when you hit the next threshold, you would only have 50 minutes left to complete the next 30 moves using the same scenario). This makes it near impossible to hit as both players receive their time allotments on the same turn.

F) One player has exceeded their allotted time, but their opponent does not have enough material to checkmate them -- This is more of a tournament forced-draw as it typically requires a 3rd party (like a tournament director or adjudicator / arbitrator) evaluation to make this ruling.

Hope this helps!

A Stalemate only occurs when a player can not make any legal moves without putting themselves into Check (but are not already in Check).

Such as in this example:

https://www.chessclub.com/assets/rules/images/Stal...

If it is the Black players turn, they can not make any legal moves.

There is no limit of moves until Stalemate occurs. It is ONLY when a player is unable to legally move.

A stalemate draw occurs when:

Player is NOT in check & is unable to make a legal move.

A stalemate occurs

It’s either 1 or 2 or both I’m not 100% sure

1. it takes more than a set amount of turns to checkmate your opponent

2. It’s literally impossible to checkmate your opponent