Training

  1. Start of training
  2. Pre-training, 8KKimi K3not stated8KNTPtext and visionMTPallMTP layer
  3. Pre-training, 64KKimi K3not stated64KNTPtext and visionMTPall
  4. Cooldown, 256KKimi K3not stated256KNTPall
  5. Cooldown, 1MKimi K3not stated1MNTPall
  6. SFTKimi K3not statednot statedSFTnot statedMXFP4 experts
  7. Cold-start model
  8. RL: nine expertsKimi K3not stated1MRLKimi K2.5’s, near GRPOnot stated
  9. Nine experts
  10. Where the student starts: not stated
  11. Multi-teacher on-policy distillationKimi K3not statednot statedMOPD9 teachersnot stated
  12. Kimi K3
  • tokens, log scale
  • derived: computed from stated numbers
  • context length
  • all parameters train
  • a part trains
  • all but a part trains
  • NTPdashed: concluded, no source names it
  • not stated by the sources
  • the architecture changes
  • checkpoint
  • checkpoint, weights published
  • a join the sources leave unexplained

Cooldown, 256K

×

Stage · Kimi K3

The third stage of the context curriculum: the window grows to 256K.

Context
256K
Data
long documents and videos; synthetic long-context tasks
Share of training
The long-sequence computation is concentrated “within a small fraction of the overall training budget”

Derived

Objective. The report describes the cooldown as the last two stages of one four-stage curriculum and names no objective for it: next-token prediction is concluded from that, and the report does not state it.

Trained. The report names no part of the model held fixed in the cooldown: that every parameter trains is concluded, and the report does not state it.

Not disclosed Tokens · Steps · Batch · Learning rate · Where each window begins · Number format

Why

The long-sequence computation is concentrated in a small fraction of the training budget, which keeps the curriculum economical while the model adapts gradually to longer dependencies. Kimi K3 report §3.4, p. 12

All settings5
Context
256K, the first window of the cooldown phase
Curriculum
Four stages: the window grows from 8K to 64K during pre-training, and from 256K to 1M during the cooldown phase
Positions
None to change: the model has no positional embedding, so the context is extended with no modification of a positional encoding
Data
Long documents and videos, cleaned and upsampled; synthetic long-context data whose tasks need information from across the full 1M context
Share of training
The long-sequence computation is concentrated “within a small fraction of the overall training budget”
Sources1