Six in the fourth place counsels a querent to strip a relationship or an obligation back to what can actually be conveyed, and then to convey it. The image is precise about the reduction: cheap vessels instead of the proper ones, and a window instead of a door. Both are breaches of the form that would apply in ordinary times, and the line states that they end without error. What is approved is not informality for its own sake but the decision to keep something alive by whatever means the danger leaves available.
The position is unusually favourable for this hexagram. A yielding stroke correctly occupies an even place, and it stands immediately below the strong fifth line, the one stable thing in the upper trigram Kan. A reading landing here typically concerns access to a person or an institution that the ordinary channels no longer reach. The counsel is to use the irregular channel and to send something plain through it rather than waiting for conditions in which the proper approach becomes possible again.
When the line changes, the upper trigram Kan becomes Dui and the figure becomes Oppression, King Wen 47, constraint with the resources spent. The transformation is a caution rather than a contradiction. The window works while there is still something to pass through it, and a connection kept alive on plain fare has a limit, which is why the line values the offering being made now above the better one imagined later.