16 Days, 4.7M Params, Zero Black Boxes: Building a White-box Chinese Cognition Engine from Scratch

Author: Wei Jinqi | June 16, 2026

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Every time I use a large language model, the same thought nags at me: I have no idea what's happening inside.

95% accuracy? Great. But which weights fired? What linguistic features were extracted? Did it confuse "bank" (river) with "bank" (financial)? Nobody knows.

So I spent 16 days building a Chinese language engine where every weight has a reason and every decision is traceable.

The Core Idea

Instead of training a transformer on terabytes of text and hoping it learns Chinese, I designed each module to handle a specific linguistic function:

Module	Function	Params
P1	Char → Word encoding	96K (frozen)
P3-L	Multi-dimensional attribute annotation	0 (rule engine)
P7	Cross-sentence word routing	226K
Explore+Meta	Learned gating over decode dims	101K
P6	Sentence → Word sequence decoding	4.37M

The modules are chained: P1 encodes → P7 routes → Gate modulates → P6 decodes. Every intermediate state can be inspected.

Day-by-Day: The Good, The Bad, and The Mode Collapse

Days 1-2: Laying Foundations (and Fighting Collapse)

Day 1 was smooth. P1 (char→word encoder) and P3 (attribute stack — a rule engine that tags words with person/syntax/semantic/emotion/direction attributes) came together quickly.

Day 2 introduced P7, the cross-sentence router. And everything broke.

I used standard multi-head cross-attention. Every position — regardless of input — routed to the same output word. The dreaded Mode Collapse.

What followed was seven failed fixes:

• v2: Diversity loss → still collapsed
• v3: Grouped loss → partially better
• v4: Temperature scaling → not enough
• v5: Contrastive learning → oscillated wildly
• v6: Gating mechanism → unstable
• v7: Hierarchical modulation → almost converged

The breakthrough came when I noticed Q/K were eye-initialized, meaning each head saw only 1 dimension with zero discrimination power.

v8 (final): Xavier init for Q/K, eye init for V. Added an Explore network (loss → GELU MLP → 64D control signal) and a Meta network (signal + state → per-word gate). Mode collapse solved.

Day 3-4: Gating Innovation and the Repetition Monster

Day 3 built P3-L: 23 groups, 312 independent attention heads, each controlling one attribute dimension. Combined training with P7 via UnifiedExplore→UnifiedMeta gate.

Day 4 introduced P6: the sentence→word decoder. It was supposed to take a 256D sentence vector and output 16 distinct word embeddings.

It output the same word 16 times. The Repetition Collapse had begun.

Six versions over two days:

• V1: 16 parallel heads → all output same word
• V2: Serial residual extraction → gradient breakage
• V3: Remove detach, add damping → gradient entanglement
• V4: Weight transpose inverse projection → too aggressive
• V5: Orthogonal init, detach, 0.8 damping → too heavy, heads dead
• V6: Position embedding — h + pos_embed[i] per head → solved

The simplest fix won. Each head receives the same h but adds a unique learned position embedding. No rep_pen. No residuals. No detach. Just position diversity.

Day 5: The Gate That Stopped Learning

Epoch after epoch, the gate stayed frozen — all 256 dimensions had std=0.0001. Three bugs conspired:

1. explore_mod.weight zero-initialized → identical signal per dim
2. p3l_act zero-initialized → sigmoid(0)=0.5 for all dims
3. bias init scale=0.1 too small → output stuck at 0.5

Then I found an even worse bug: gate.item() was used in loss computation, converting a tensor to Python float — severing the gradient chain. The gate had been frozen for 240 epochs without anyone noticing.

Fix: keep gate as tensor, let gradients flow back through explore and meta. Loss dropped from 0.56 to 0.28 in 3 epochs.

Day 6: The AI That Debates Itself

I built a dual-agent debugging system: DeepSeek (engineer) proposes fixes, Qwen (reviewer) audits them. They debate until convergence.

The system diagnosed four major bugs, including the gradient chain break. It would have saved days if I'd built it earlier.

Days 7-11: From 875K to 4.7M — Scaling Up

Key improvements:

• Replaced mean pooling with P5-style ±superposition for sentence vectors
• Expanded P6 from 16 heads to 128 independent heads
• Built Context Cache System: 3-tier (GPU/RAM/Disk), adaptive retrieval window, drift detection
• First benchmark: 92.4% word accuracy on 875K-param V18

Days 12-16: CUDA Wars and Open Data

• Conquered CUDA OOM (P1 full attention → batch encoding)
• Fixed space-character collapse (HF data had spaces between Chinese chars → ord(c) > 32 filter)
• Assembled 52K public training pairs from HuggingFace + MuCGEC
• Launched V19 1000-epoch training: 4.7M params, 141MB GPU, 100% public data

Seven Bugs That Almost Won

Bug	Symptom	Root Cause	Fix
Mode Collapse	All outputs = same word	Q/K eye-init, zero discrimination	Xavier init + diversity architecture
Gate Symmetry Lock	All gate dims identical (std=0.0001)	Three zero-initializations	Proper random init for explore, act, bias
Gradient Chain Break	Gate not learning for 240 epochs	.item() severed gradient	Keep as tensor
Repetition Collapse	16 heads → same word	Parallel heads share identical input	Position embedding V6
CUDA OOM	25.76 GiB allocated	P1 full cross-attention	Batch encoding (50 words)
Space Collapse	Model outputs spaces	HF data formatting	ord(c) > 32 filter
sent_vec Info Loss	Different sentences → similar vectors	Mean pooling	Learnable ±weighted sum

Results

V18 (875K params)

Metric	Score
Word Accuracy	92.4%
Exact Match	76.3%
Rouge-L F1	93.2
Per-word Cosine	0.96
Speed	14ms/sent (71 sent/s)

V19 (4.7M params, training in progress)

Epoch 1 (from scratch, no pretraining): 43.5% word accuracy on held-out exam set. Target: >95% after 1000 epochs.

Why This Matters

LLMs are powerful but opaque. When GPT makes a mistake, you can't trace which neurons fired wrong. With V19, you can:

• See exactly which word attributes were used
• Trace which input words influenced each output
• Inspect why the gate opened or closed each dimension
• Debug layer by layer, like stepping through code

This isn't about beating GPT. It's about building something you can understand completely.

What's Next

• Context system "write path": feed retrieved context into P7 to enable multi-turn dialogue
• Expand to 512-dim if quality plateaus (currently 128D)
• Multi-language extension of the attribute stack (P3-L)
• Open-source community contributions

Try It

git clone https://github.com/Xuan-yi-yan/V18-cognitive-architecture
cd V18-cognitive-architecture
python download_public_data.py
python train_v19_full.py --data public --epochs 1000 --display 10

Full model card and architecture docs on Hugging Face.

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16 days. 7 dead bugs. 4.7 million parameters. Zero black boxes.

That's just how I like it.