Kikashi and mochikomi

Published 3 Sep 2020 by antti (last edited 3 Sep 2020)
tags: terms

Kikashi and mochikomi are probably two of the most misunderstood and misused go terms. They are also two of the most unnecessary Japanese terms that still see use in English go jargon; this is because the same information can easily be conveyed by normal language without needing to resort to arcane Japanese terms.

Kikashi, or good exchange

A long time ago, when I was starting to really understand the concept, I wrote a needlessly long-winded essay on kikashi on my old blog at

Not too long after my having published the essay, I heard one of my teacher’s other students ask her what ‘kikashi’ means in English, and she immediately responded with ‘good exchange’. This was akin to an epiphany to me, as I realised that my flailing attempt at trying to classify different types of kikashi, as in the linked article, failed in comparison to this simple interpretation of the core meaning of the term.

The exchange of black 1 for white 2 constitutes a kikashi, or a ‘good exchange’. After the exchange, Black does not have to continue playing locally, and the stone at 1 still functions as both a ladder breaker and an eye-space-reducing move. Compared to 1, white 2 is worth less as a stone, as it is only reinforcing a connection that White already had before 1.

Mochikomi, or uncompensated sacrifice

Unlike kikashi, mochikomi does not have a very snappy English counterpart; but in exchange, it is also much less used as a concept. In fact, I imagine many readers are not even familiar with mochikomi as a go term.

Mochikomi literally means ‘carrying in’, but this does not give us a very good idea on what it means in go. Various Japanese go dictionaries explain it thus: ‘playing within the opponent’s area and getting captured, constituting an overall loss.’ Therefore, if one forcefully wanted to create an English counterpart for the term, ‘uncompensated sacrifice’ is probably one of the better options.

The above description and English translation have the problem that they depend on complex definitions: what is a player’s ‘area’ and what does ‘uncompensated’ exactly mean? Therefore, it can be better to forget about the concept of mochikomi altogether, and instead focus on whether one’s stones are working effectively enough.

The sequence of 1–6 is an example of Black forming a mochikomi. When breaking the sequence into parts, the exchange of black 3 and 5 for white 4 and 2 would be more or less fair, but the exchange of black 1 for white 6 merely increases White’s territory. Therefore, we say black 1 forms a mochikomi.
3: elsewhere
If White first responded to black 1 with 2, Black played elsewhere, and then 4–8 followed, now black 1 is no longer a mochikomi. This is because now White has added an extra stone at 1 inside his own territory. If we imagine black 1 and white 2 did not exist, then it is clear that the rest of the exchange is not bad for Black.

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