Lecong Zhang
Lecong Zhang is a member of the DeepSeek-AI team in Hangzhou, China, and a coauthor of the DeepSeek language-model reports published between 2024 and 2026. Their name appeared on DeepSeek LLM in January 2024, on the Mixture-of-Experts model DeepSeek-V2 in May 2024 and on DeepSeek-V3, a model with 671B total parameters, in December 2024. In January 2025, the DeepSeek-R1 report showed that pure reinforcement learning can draw out reasoning in large language models, and Nature published the work in September 2025. Later reports by the team, each crediting Zhang, covered DeepSeek-V3.2 in December 2025, the million-token DeepSeek-V4 series in April 2026 and the KV-cache-saving DeepSeek-V4.1-Flash in September 2026.
- Now at
- DeepSeek
Timeline
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January 2024
The DeepSeek LLM report
In January 2024, they are among the DeepSeek-AI authors of DeepSeek LLM, a project to scale open-source language models in 7B and 67B configurations. The team builds a pre-training dataset of 2 trillion tokens, and DeepSeek LLM 67B surpasses LLaMA-2 70B on various benchmarks.
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May 2024
Mixture of experts in DeepSeek-V2
Zhang coauthors DeepSeek-V2, posted in May 2024, a Mixture-of-Experts language model with 236B total parameters, of which 21B are active for each token. The model uses Multi-head Latent Attention and DeepSeekMoE, and reduces the KV cache by 93.3% compared with DeepSeek 67B.
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December 2024
The DeepSeek-V3 technical report
The DeepSeek-V3 technical report of December 2024 lists Zhang among its authors. The model has 671B total parameters with 37B activated for each token, is pre-trained on 14.8 trillion tokens, and needs 2.788M H800 GPU hours for its full training.
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January 2025
The DeepSeek-R1 report
They coauthor DeepSeek-R1, posted in January 2025, which shows that the reasoning abilities of large language models can be incentivized through pure reinforcement learning. The trained model performs strongly on mathematics, coding competitions and STEM tasks.
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September 2025
DeepSeek-R1 in Nature
Nature publishes the DeepSeek-R1 work in September 2025, listing Zhang among the authors from the DeepSeek-AI Team in Hangzhou, China.
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December 2025
Sparse attention in DeepSeek-V3.2
In December 2025, Zhang is an author of DeepSeek-V3.2, which introduces DeepSeek Sparse Attention to cut computing costs in long-context scenarios. Its high-compute variant, DeepSeek-V3.2-Speciale, reaches gold-medal performance at the 2025 International Mathematical Olympiad and the International Olympiad in Informatics.
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April 2026
Million-token DeepSeek-V4 models
The DeepSeek-V4 preview report of April 2026 lists them among its authors. It presents DeepSeek-V4-Pro with 1.6T parameters and DeepSeek-V4-Flash with 284B parameters, both supporting a context length of one million tokens.
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September 2026
KV cache compression in V4.1-Flash
In September 2026, they appear among the DeepSeek-AI authors of DeepSeek-V4.1-Flash, a multimodal Mixture-of-Experts model with 552B backbone parameters and contexts of up to one million tokens. Its design shrinks the global KV cache to 890 bytes per token.
Sources and credits
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- [2401.02954] DeepSeek LLM: Scaling Open-Source Language Models with Longtermism
- [2405.04434] DeepSeek-V2: A Strong, Economical, and Efficient Mixture-of-Experts Language Model
- [2412.19437] DeepSeek-V3 Technical Report
- DeepSeek-V3 Technical Report | Cool Papers - Immersive Paper Discovery
- [2501.12948] DeepSeek-R1: Incentivizing Reasoning Capability in LLMs via Reinforcement Learning
- DeepSeek-R1 incentivizes reasoning in LLMs through reinforcement learning | Nature
- [2512.02556] DeepSeek-V3.2: Pushing the Frontier of Open Large Language Models
- [2606.19348] DeepSeek-V4: Towards Highly Efficient Million-Token Context Intelligence
- [2609.19969] DeepSeek-V4.1-Flash: Pushing the Limits of KV Cache Compression