Week 91: Pirc vs Modern Defense, a 4–0 and a 0–3 in the same week
Week 91 (October 20 to 26, 2025) got me back over 1200: 19 rapid games, 11 wins and 8 losses, from 1177 to 1202. As Black I played 1...g6 almost every game, and the week split into a strange Pirc vs Modern Defense comparison. The games Chess.com labelled Modern Defense went 4–0. The games labelled Pirc Defense went 0–3. Same first move, same pawn on d6, very different results.
The week in numbers
| What | This week |
|---|---|
| Rated rapid games | 19 |
| Score (W–L–D) | 11–8–0 |
| Rating change | +25 (1177 to 1202) |
| Average accuracy (Stockfish) | 78.4% |
| My blunders | 34 |
| Openings I played most | London System (3), Modern Defense with 1 e4 (3), Queen's Pawn Opening Zukertort Chigorin Variation (2) |
The other unusual number this week: 21 of my 34 blunders came on move 15 or earlier, and 12 were classified as opening moves. In most weeks of this diary the opening is my safest phase. Not this one. On the positive side, several games were very clean, including 97.4% (game 1742), 96.5% (game 1745) and 95.6% (game 1729).
Pirc vs Modern Defense in my own games
Here's what actually happened in the five games behind that 4–0 and 0–3:
- Modern, 4–0. Against Sparsh0506 (90.5%), Ashoka101, LOOSCROOS (90.6%) and fossmajiggy (97.4%). The openings were varied: an early Bc4, an early Qf3, a London-style Bf4 against 1.d4 g6, and one game where the queens came off on move 4 after 1.d4 g6 2.e4 d6 3.e5 dxe5 4.dxe5 Qxd1+.
- Pirc, 0–3. Against le-el (43.6%), r00k13s4n (72.1%) and Pragyansh_chess (59.2%). In two of them White set up with Nc3 and an ambitious plan: Bc4 and f4 in game 1734, Be3 and Qd2 in game 1744. In game 1747, the Geller System, White played an early Bc4, Ng5 and Qf3, and the game was over after my eighth move.
I don't think the opening names explain the scores by themselves. In the Pirc games I blundered early: 5...e5 in game 1734 (from +0.23 to +2.46), 6...Bxg5 in game 1747 (+0.21 to +6.44). But it's a useful warning. When White sets up with Nc3 and a plan like f4, or Be3 and Qd2, I need to slow down. I'm not finding the same easy positions I get in the Modern.
Three positions from the week
Against surafel111 (1206), in a King's Indian setup (1.d4 g6 2.e4 d6 3.c4), my queen had gone hunting: 9...Qxb2, then 10...Qa3 and 11...Qa6. White was better (+2.19). I played 12...b5 and it got worse (+5.15). Stockfish's 12...Qa5 attacks two things at once, the knight on c3 and the pawn on c5, which had no defender. I won this game anyway, by checkmate on move 61 with 32 seconds left, after 16 moves in time trouble. It's not a game to copy.
This is the most basic tactic of the week and I missed it, for one move. Against 99NoahC (1214) I was winning (+3.52). 14.Nc6+ is a knight fork: the knight gives check to the king on b8 and attacks the rook on d8 at the same time. The king must move, and the rook falls. I played 14.a5 instead, and Stockfish's best reply for Black, 14...Nxe5, would have removed my knight and made it about equal. My opponent didn't see that either and played 14...a6, and this time I did play 15.Nc6+, winning the rook after 15...Ka8 16.Nxd8. Right after that I gave most of it back with 17.Nf3 and 18.Ne5, both mistakes, and I lost by checkmate on move 42.
The last one, against Ashoka101 (1178), is a Modern win with a lesson I didn't take. White's 14.g4 was a blunder that attacked my knight on h5. I retreated it, 14...Ng7, and the evaluation went from -4.50 (good for me) to +1.43. Stockfish ignores the knight: 14...e5 attacks White's queen on d4, and after 15.Qxe5 my bishop takes the pawn on g4, the very pawn that attacked my knight, and now attacks the knight on f3. A counterattack on the queen first, then capture the attacker. I won when my opponent abandoned the game on move 48, but not because of this move.
The lesson of the week
A few weeks ago my lesson was "answer the threat against you before making your own". This week Stockfish showed me the exception, and it's worth stating precisely: when your piece is attacked, first check for a move that attacks something bigger, like the queen, and gains the time to deal with the threat afterwards. 14...e5 in game 1733 did that. My other lesson is plainer: look for checks first. 14.Nc6+ was a check, and I didn't look at it until my opponent gave me a second chance.
All games this week
| # | Date | Colour | Opponent | Result | Opening | Accuracy | |
|---|---|---|---|---|---|---|---|
| 1729 | 2025-10-20 | White | HeH0107 (1176) | Win | London System | 95.6% | game |
| 1730 | 2025-10-20 | Black | Sparsh0506 (1165) | Win | Modern Defense with 1 e4 | 90.5% | game |
| 1731 | 2025-10-20 | Black | surafel111 (1206) | Win | King's Indian Defense Normal Variation | 94.6% | game |
| 1732 | 2025-10-21 | White | 99NoahC (1214) | Loss | Queen's Pawn Opening Zukertort Chigorin Variation | 78.7% | game |
| 1733 | 2025-10-22 | Black | Ashoka101 (1178) | Win | Modern Defense with 1 e4 | 76.7% | game |
| 1734 | 2025-10-22 | Black | le-el (1187) | Loss | Pirc Defense Main Line Kholmov System | 43.6% | game |
| 1735 | 2025-10-22 | White | Darkreddd (1201) | Win | Modern Defense with 1 d4 | 75.2% | game |
| 1736 | 2025-10-23 | White | Sameh7771 (1208) | Loss | Queen's Pawn Opening Zukertort Variation | 89.8% | game |
| 1737 | 2025-10-24 | Black | playfairJust (1254) | Win | Nimzowitsch Defense Declined Williams Variation | 58.3% | game |
| 1738 | 2025-10-24 | Black | XrXremmanuel480E40440 (1229) | Loss | Nimzowitsch Defense Declined Williams Variation | 43.8% | game |
| 1739 | 2025-10-24 | Black | LOOSCROOS (1182) | Win | Modern Defense with 1 d4 | 90.6% | game |
| 1740 | 2025-10-25 | White | faisalalharbi911 (1209) | Win | Queen's Pawn Opening Zukertort Chigorin Variation | 66.8% | game |
| 1741 | 2025-10-25 | White | RDXC4 (1225) | Loss | Queen's Pawn Opening Accelerated London System | 94.0% | game |
| 1742 | 2025-10-25 | Black | fossmajiggy (1026) | Win | Modern Defense with 1 e4 | 97.4% | game |
| 1743 | 2025-10-25 | White | BPK7 (1239) | Loss | London System | 76.8% | game |
| 1744 | 2025-10-25 | Black | r00k13s4n (1222) | Loss | Pirc Defense Main Line | 72.1% | game |
| 1745 | 2025-10-26 | White | yassinabrd63 (1204) | Win | Indian Game East Indian London System | 96.5% | game |
| 1746 | 2025-10-26 | White | abid3o1 (1187) | Win | London System | 88.8% | game |
| 1747 | 2025-10-26 | Black | Pragyansh_chess (1223) | Loss | Pirc Defense Modern Defense Geller System | 59.2% | game |
Previous week: week 90. Next week: week 92. The whole journey is on the journey page. If you play the Pirc or the Modern, you can review your own games like this.
Frequently asked questions
What is the difference between the Pirc and the Modern Defense in my games?
Both start with ...g6 and ...d6 in my games, and Chess.com's label depends on the exact move order. My plans were close in both; the results this week were not: 4-0 in the Modern lines, 0-3 in the Pirc lines.
Which scored better for me, Pirc or Modern?
This week, as Black, the Modern games went 4-0, with 97.4% and 90.6% accuracy in two of them. The Pirc games went 0-3, at 43.6%, 72.1% and 59.2%.
What is a knight fork?
A knight move that attacks two pieces at once. In game 1732, 14.Nc6+ would have checked the king on b8 and attacked the rook on d8 at the same time. I missed it for one move, played it the next turn, and won the rook.