🌟 Day 4 – Diving Into the First Pillar: Chunking
A few weeks ago, I wrote a post saying I had zero idea what “chunking” even was. Now, a few weeks later I definitely understand more, but not enough.That’s why today is fully dedicated to Pillar 1: Chunking.
Back then I got great examples:
🍞 “Slice a loaf of bread into pieces.”
🍕 “Cut a pizza into slices.”Perfect analogies — and still true.
But now I understand why chunking is so important:
🔹 What Chunking Really Is
Chunking is the most critical preprocessing step in any RAG system. IT means breaking large documents into smaller, meaningful segments (“chunks”), which are then embedded, indexed, and retrieved later.
Chunks are the atomic information units your RAG system uses.
If the chunks are bad, retrieval is bad — and the LLM can’t fix it.
🔹 The Core Dilemma
Chunking is always a balance between:
1️⃣ Precision – smaller chunks give cleaner embeddings
2️⃣ Context – bigger chunks give more meaning to the LLM
Too big → diluted meaningToo small → missing context→ And THAT is the hardest challenge in chunking.
🔹 Best Practices for Chunking
Here are the key strategies I’m learning:
📌 Recursive Character
ChunkingRespects natural text boundaries (paragraphs, sentences).Often the recommended default.
📌 Overlap (10–20%)
Ensures context isn’t lost at the edges.Example: 500-token chunk → 50–100-token overlap.
📌 Optimal Sizes
A strong starting point is 512–1024 tokens per chunk.
📌 Advanced Methods– Semantic
Chunking: uses embeddings to detect topic changes– Agentic Chunking: LLM splits text into atomic, meaningful statements
These methods help avoid context loss and improve retrieval quality.
🔹 Why This Matters
Chunking literally determines what your RAG system can find.And if retrieval fails, the LLM fails — it can’t magically invent the missing context.
All resources, diagrams, and notes as always:👉 Notebook: https://notebooklm.google.com/notebook/ea1c87b2-0eda-43f8-a389-ba1f57e758ce
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Holger Peschke
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🌟 Day 4 – Diving Into the First Pillar: Chunking
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