49 days to 21.1 km.

Easy runs are really easy. Most beginner injuries come from running easy days too fast, or from adding a fourth and fifth run before the legs are ready.

The plan adds at most 3 km of running to a week and 2 km to the long run. Do not add more on your own, however good you feel.

Never run through sharp or worsening pain. Take an extra rest day instead.

Missed a run? Skip it. Do not stack two hard days to catch up.

Lost a whole week to illness or travel? Repeat the week before it, then rejoin. Lost two? The plan drops the long run back for you; check the next checkpoint honestly.

Long runs are continuous from week 3, walking only to drink. The race-pace blocks are even: the last km is the same pace as the first.

One workout a week, on Thursday. Hit the pace, do not beat it. If you are ill, sore or short on sleep, run it easy instead.

Sleep is training. Aim for 7 to 8 hours, especially the night before long runs.

Your best sustained effort is 3.3 km at 6:44 per km (Oct 1): about a 34:30 5K and a 1:13 10K today. 2:40 needs about a 70-minute 10K by December. It is a stretch, and that is the point of the block.

Your breathing is ahead of your legs. That is why the gym is about legs and the workouts build slowly: the engine is there, the chassis is still catching up.

Easy runs: 8:40–9:15/km. The block so far averages 8:06, about 35 seconds too fast. Effort leads, the watch only checks. Easy means full sentences.

Long runs: 8:50–9:20/km for the easy part.

Race pace: 7:35–7:40/km, continuous, for 2:40–2:45.

Workout paces: 1 km reps at 7:10 to 7:15, 2 km reps at 7:15 to 7:20, race-pace blocks at 7:35 to 7:40. Every other run stays easy, by the talk test.

The pace guide is a ceiling on easy days, not a target. If your easy pace drifts faster while you can still talk in full sentences, that is fitness arriving.

The 7:30s in your log are moving-time paces. They leave out the pauses. A race clock does not.

October is humid. Go by the talk test and expect to be 20 to 40 seconds per km slower than the same effort in December. Start by 6 am and carry water past 45 minutes.

Pune on a December morning is cool. That is worth 15 to 25 seconds per km for free, and it will tempt a fast start.

Monday is the rest day. Four runs are the plan: Tuesday, Thursday, Friday, Sunday. Wednesday is one 40-minute gym session; Friday adds 15 minutes of home strength after the run; Saturday's swim is optional.

The gym is the one support session to fight for: stronger legs are what let the long runs grow. The swim can go whenever life is busy. Neither ever counts as missed.

Want more? Add minutes in the pool or a set in the gym. Do not add running: the running grows 3 km a week on purpose.

A run done a day early or a day late still counts for that week.

A missed easy run is released, not rescheduled. The long run is the one to protect.

Sunday's long run never jumps more than 3 km past your longest run of the last four weeks.

In a week with fewer than two other runs, Sunday repeats instead of climbing. The ladder is earned midweek.

Legs in the gym go light from week 8, and race week is upper body and core only.

Three checkpoints decide the race plan: Oct 31 (is the base there), Nov 8 (is the pace there), Nov 29 (is the distance there).

The plan is honest about the goal. If the Nov 8 trial is over 74 minutes, 2:40 moves to the next half and Pune is raced for 2:50.

Thu to Sat — More carbs than usual, a normal amount of protein, no new foods.

Fri Dec 11 — Rest. Drink water through the day. Pack everything, including shoes you have already worn on long runs. Friday's sleep matters more than Saturday's.

Sat Dec 12 — 2 km shakeout, collect your bib, then feet up. Carb-heavy dinner early: rice, pasta or roti, nothing new or spicy. In bed by 9:30 pm.

Sun Dec 13 — Wake 3 hours before the start. A light breakfast you have eaten before long runs (banana, toast, oats) 2 to 3 hours before. Sip water, a final toilet stop, and get to the start early.

The goal — 2:40 is 7:35 per km; 2:45 is 7:49. The Nov 8 trial and the Nov 29 18 km decide which. The 3:00 cut-off (8:31) is not in play at either pace.

Running — Continuous. Walk only 15 to 20 seconds through water stations, drinking as you go. Every other step is running.

First 3 km — 7:45 per km. The cool air and the crowd will make this feel too slow. That is the point: 30 seconds banked early costs 3 minutes late.

Km 3 to 16 — 7:32 to 7:35 per km for 2:40 (7:45 to 7:49 for 2:45). Even, like a metronome. No faster downhill or when the crowd cheers.

Fuel — Water at every station. A gel at about km 6, 11 and 16, with water.

Last 5 km — Whatever is left. This is the only place to push.

Plan B — If your average is slower than 7:45 at km 10, settle into the 2:45 pace instead of chasing. If it gets hot or ugly, a one-minute walk every 4 km still finishes near 2:50.

Heat or pain — If you feel dizzy or a sharp pain, walk. A finish matters more than the time.

Nothing new — No new shoes, socks, gels or kit. Race in shoes that have done at least 50 km, including one long run.

before — walk 3 minutes, 10 leg swings each side, then make the first kilometre your easiest.

after — walk 2 minutes and stretch calves, quads and hamstrings.