Easy Chunking Question 65 of 223

What is overlap in document chunking?

GenAI / LLM · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: A SENTENCE BECOMES TOKENS

The model does not read letters like humans. It reads these pieces, then predicts the next one.

Simple meaning

Overlap copies a few tokens or sentences from the end of one chunk into the start of the next.

WHY — Tokens instead of words?

LLMs use tokens (not full words) because it helps them:

Chunking questions separate people

who only read docs from people who shipped.

Keep it short, concrete,

and tied to GenAI / LLM work.

Stable token IDs

Each piece maps to a number the network can learn.

Fits the model

Fixed pieces are what transformers expect as input.

STEPS — What happens with tokens?

Before the model can read a sentence, it goes through these steps:

1
Overlap copies a few
tokens or sentences from the end of one chunk into the start of the next.
2
It reduces the chance
that a fact is split across a boundary.
3
Too much overlap wastes
index space and duplicates hits.
4
Context mix
Attention looks at nearby tokens together.
5
Next token
The model scores what should come next.
6
Decode
IDs turn back into readable text.

EXAMPLE — See it in action

Here's a short line you can speak, broken into clear beats:

Say this line

“It reduces the chance that a fact is split across a boundary.”

Break into beats

Itreducesthechancethata

Speaking order

2987408337471632900

Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Key takeaway

Overlap copies a few tokens or sentences from the end of one chunk into the start of the next. It reduces the chance that a fact is split across a boundary.