3453 enclosure  

This is the small knight's corner enclosure or small low enclosure, composed of a stone on the 3-4 point and one on the 5-3 point. With two moves, Black takes full control over this corner, making it very likely that it will turn into territory. Compared to larger and higher enclosures, it emphasizes stability over development, territory over influence.

Enclosure opening  

There was a period in the years around 1960 when this -- formation for Black was the most popular of all opening patterns. That was in the days of 4.5 komi (as the general rule - see komi Go). This enclosure opening has never been refuted, of course - it is hard to imagine such a thing. It does convey the attitude that Black can do well enough by tight, territorial Go.

With komi becoming universally adopted, White saw less need to forestall by playing an approach in that corner as (leading on to a Shusaku fuseki pattern). Nowadays the Orthodox fuseki has to some extent taken the place of this opening, as a solid way to play; of course then Black is less likely to play a pincer joseki. When White approaches at a Black can indeed play a good pincer on the upper side. For White at b this isn't such a clear-cut issue.

White's techniques  

One effect of the intensive use of this enclosure is that White's various reduction and probing techniques have been thoroughly researched.

1. White has reduction plays at a, see 3-4, 5-3 enclosure, capping reduction and b, see 3-4, 5-3 enclosure, shoulder hit reduction ;
2. White has c builds up the left side but Black will normally develop on the top side; see 3-5 attachment against a low corner enclosure
3. White d and e are useful probes, depending on whether the left side or top side is more interesting as an area in which White would like some stones. See 2-4 Probe against a low corner enclosure and 3-4, 5-3 enclosure, 4-3 invasion