How often do players deviate from book moves in the Queen's Gambit by move 5? (in Rapid Chess) **Research Needed:** Ana

· Chess Research

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The grandmaster-guide MCP server is currently running in a degraded state and cannot support this research task. Per the project instructions, I am stopping rather than powering through without it.

Diagnostic summary from this session (all times UTC-4, 2026-04-21 ~05:15–05:35):

Endpoint Result
list_api_endpoints (MCP) First call failed with service is running in degraded mode, MCP connections unavailable; later retries intermittently succeeded.
GET /api/lichess-analytics/provenance 200 OK, 646 bytes — the only consistently healthy endpoint.
GET /api/python-analyzer-status 200 OK, ready.
GET /api/theoria-status 200 OK, ready.
GET /api/lichess-analytics/opening-search?q=Queen ~20 consecutive attempts: mix of HTTP 200 with 0 bytes, HTTP 502 Bad Gateway, and curl: (18) transfer closed with outstanding read data remaining. Never returned a usable JSON body.
GET /api/lichess-analytics/opening-deep-stats?eco=D30 (and D2, D) Same failure pattern — 200/empty or 502 across 15+ retries.
GET /api/lichess-games?limit=2…5 (the bulk PGN endpoint needed for this analysis) Same failure pattern — transfers cut off mid-stream, 0-byte responses.
GET /api/lichess-games?limit=1 Occasionally returned a single game (~1 success out of 5 offsets tried), but at 1 game per request with high failure rate it would take many hours to gather even 5,000 rapid games, and the project hard-caps the run at 60 minutes.
MCP tool calls (api_lichess_analytics_opening_search, api_lichess_analytics_opening_deep_stats, api_lichess_analytics_opening_winrates) Consistently returned Error: terminated / transport error: unexpected nil response.

Conclusion: The analytics endpoints I would use to characterise Queen's Gambit play (opening-search, opening-deep-stats, opening-decay-curve) are unreachable, and the bulk PGN endpoint is too unreliable to assemble a 5,000+ game rapid sample within the time budget. The project instructions explicitly say:

"at any time if any of the tools in the grandmaster-guide mcp goes down, error out don't attempt to finish analysis without it."

and

"If the task takes more than 60 minutes, create the article with the data u have or error out saying its not possible."

Because I have no usable data to base an article on (only provenance/health pings succeeded), I am erroring out. Please retry once the grandmaster-guide MCP is healthy again — a simple sanity check is whether https://abc5000.share.zrok.io/api/lichess-analytics/opening-search?q=Queen returns a non-empty JSON body.

— Chess Coach · 21 April 2026

Frequently Asked Questions

What is this Queen's Gambit research article trying to measure?

It is trying to measure how often Rapid Chess players leave book moves in the Queen's Gambit by move 5. The goal is to quantify early opening deviation rather than evaluate the position itself.

Why was the analysis not completed?

The analysis was stopped because the grandmaster-guide MCP server was running in a degraded state. The needed opening and game-data endpoints were unreliable or returned empty responses.

Which data source was still working during the session?

The /api/lichess-analytics/provenance endpoint was the only consistently healthy endpoint. Other endpoints needed for opening search, deep stats, and game retrieval were failing intermittently or returning unusable data.

What happened when the opening search was queried for Queen's Gambit data?

The opening search endpoint repeatedly returned either empty 200 responses, 502 Bad Gateway errors, or truncated transfers. It never produced a usable JSON result for the research task.

Why is move 5 an important cutoff in opening research?

Move 5 is a common point for measuring whether players are still following established opening theory or have already deviated from book moves. It gives a simple early-opening snapshot of preparation in Rapid Chess.

Does this article provide the final deviation rate for the Queen's Gambit?

No. The excerpt documents the failed research attempt and the technical blockers, but it does not include a final deviation percentage or completed statistical result.

Is this article about a specific chess opening line or a general opening study?

It is a general opening study focused on the Queen's Gambit in Rapid Chess. The article is about book-move deviation by move 5, not a single named variation.